From pickle juice to chemosensation: A discussion on the interoceptive/homeostatic reset system for interventions in dissociation and trauma-related dysregulation

Comments by readers on application of pungent foods and other tastes and odours in their own clinical work

In response to our article, Bruce Bean, whose work we had built upon (Murray, 2016; The People’s Pharmacy, 2017), wrote, ‘By the way, one way of increasing the “jolt” from TRP channel activation would be to add a bit of concentrated ginger juice (which you can buy on Amazon) to pickle juice. I think you could probably come up with a mixture that was powerful but still palatable’ (Email communication, 13 January 2026). Along the same lines Lee Crothers, a Melbourne occupational therapist and psychotherapist, reported ‘I have a client who chose to use ginger shots and wasabi to “come back to themselves.” It helped reduce self-harm as this was often used to bring them back to their body’ (LinkedIn communication, 18 January 2026).

Many clinician readers, including occupational therapists (OTs), physiotherapists, and neuropsychiatrists, wrote us to say that they were already using a range of pungent foods – chilli, apple cider vinegar, mint, ginger, têtes brûlées candies (France), pepper, umeboshi plums (Japan), and lemon in water – as part of their clinical practice.

Lucia Tesolin, a neurologist working in Peru, wrote that in that cultural context ‘we have many culturally congruent, accessible and well-accepted TRP-activating options. Foods such as ají, lime and rocoto, kión (ginger) (core ingredients of Peruvian cuisine), and even Inca Kola carbonated drink, the national counterpart to Coca-Cola, are easily available in any local street market. I already use some of these pungent stimuli routinely with patients experiencing dissociative symptoms, precisely because they are familiar, inexpensive, and immediately accessible in daily life’ (Email communication, 20 January 2026). Subsequently, Lucia also mentioned that ‘one particularly relevant and culturally embedded option [is] muña leaves [Andean mint], which are widely used by the local population as infusions accompanying meals, often replacing plain water. They provide a strong, familiar aromatic stimulus that is very well accepted by patients and recognized as an arousing stimulus’. Lucia also shared that she was coordinating a project that included group cognitive-behavioural therapy/aromatherapy sessions for patients with functional/dissociative seizures. ‘During these sessions, patients [are] exposed to different odors and tastes . . . in order to explore the individual bodily responses to these sensory inputs while patients were in a state free of symptoms, and to help them learn how to intentionally use such stimuli when dissociative symptoms arise’ (Email communication, 20 January 2026). Lucia’s comment raises a question as to the neurobiology of aromatherapy: is the mechanism by which pleasant odours engage neural mechanisms the same or different to the mechanism engaged by pungent foods. We answer this question in the latter part of this article.

Two experienced occupational therapists working with functional neurological disorder (FND) described their own use of pungent tastes – such as mint-flavoured mouthwash and lemon juice – during the warning-symptoms phase of functional/dissociative seizures. One of them, Mary Mathews (Brisbane) also reported that in her group intervention for functional/dissociative seizures, a number of patients were now utilising pickle juice at the earliest sign of an imminent functional/dissociative seizure, with positive response (LinkedIn communications, 28 January and 25 February 2026).

Kate Gill, president and founder of FND Australia Support Services, noted that the homeostatic sensory-reset hypothesis aligns with the commonly used FND metaphor distinguishing between hardware and software dysfunction, framing the intervention as analogous to restarting a computer program rather than repairing structural pathology (Teaching session, 2 February 2026).

The neurologist Jeff Waugh of the University of Texas Southwestern told us about the use of a TRP-activating food for functional neurological symptoms not included under the rubric of functional/dissociative seizures. He reported that one of his patients, a child with functional movements, used peppermint candies because the sharpness of the favour helped her break out of episodes (Email communication, 13 January 2026). Menthol is the primary active component of peppermint and activates a certain class of TRP channels (the TPRM8, the cold and menthol receptor).

Stella Li, a clinical psychologist at the Children's Hospital at Westmead (Australia), wrote, ‘Basically, intense sensations including touch, taste, and smells have been used as distress tolerance skills in DBT [dialectical behaviour therapy]. These can be using calming and comforting smells to self soothe or intense tastes or smells like lemons or I guess pickle juice! Marsha Linehan suggests they work by shifting attention away from internal distress/turmoil to external sensory input aka grounding. I have found them very effective clinically, especially with dysregulated teenagers’. In the DBT theoretical framework, intense sensory input is conceptualised as helping to shift attentional focus or reduce arousal during acute distress (Linehan, 2015). Our homeostatic sensory-reset hypothesis adds a new perspective. It proposes that a homeostatic sensory-reset mechanism is also at play. Notwithstanding, Stella Li’s comment – as well as comments from other readers – raises an important question: do pungent foods shift focus-of-attention, and is this shift of attention part of the proposed homeostatic sensory-reset mechanism? We address this question in the latter part of this article.

And finally, two of the authors – CF and JO – have been working with patients to examine whether pungent foods might be useful in the management of hallucinations, panic symptoms, and ‘autistic meltdowns’. Akin to functional/dissociative seizures, these presentations are all characterised by a state of high arousal associated with a subjective sense of sensory or emotional overwhelm. CF and JO have developed a Homeostatic Sensory-Reset Worksheet for clinicians (Fitzgibbon and O’Sullivan, 2026).

Use of pickle juice and other pungent foods with posttraumatic stress disorder

We received the question ‘have you used the pickle juice and other pungent foods for posttraumatic stress disorder (PTSD)?’ and presume that the question concerns the use of pungent foods in relation to the re-experiencing subtype of PTSD. The answer to this question is yes. In our original article, in order to keep the text focused, we had focused on the use of TRP channel activators in shutdown states, including the dissociative PTSD subtype (see Vignettes 1 and 2 in the original article) (O’Sullivan et al., 2026). In the clinical setting, however, we use TRP channel activators in PTSD to both help individuals disrupt dissociative shutdown states (dissociative subtype of PTSD) and also to help individuals disrupt flashbacks (re-experiencing subtype of PTSD). A longer version of our answer is found below.

Individuals who are diagnosed with PTSD fall into one of three groups: those who re-experience the trauma (re-experiencing subtype of PTSD), those who retreat into a ‘shutdown’ state (dissociative subtype of PTSD), and those who experience both symptom patterns (Lanius et al., 2002; Lanius et al., 2003; Nicholson et al., 2017).

– The re-experiencing subtype involves under-modulation of the periaqueductal grey (PAG) and amygdala alarm centres, along with under-modulation of arousal and somatosensory information, with the consequence that the individual is flooded with negatively valanced sensory stimuli (see Figure 1) (Kearney and Lanius, 2022).OPEN IN VIEWER

Viewed via the lens of somatosensory processing – as proposed by Breanne Kearney and Ruth Lanius – PTSD can be conceptualised as a loss of balance or an ‘off balance’ in the neural pathways crucial for the processing and integration of somatic, or body-based, sensations as a result of trauma experiences (p. 2) (Kearney and Lanius, 2022).

In the dissociative PTSD scenario, the homeostatic-reset hypothesis patients can use TRP channel activators to give the interoceptive/homeostatic/system a ‘jolt’, as it were, overriding the top-down over-modulation and resetting the system, thereby allowing somatosensory information to ascend from the body to the brain. Because TRP channels are also activated by sensory stimuli such as pain, temperature, acid, inflammation, and other noxious stimuli – all of which may signal ‘danger’ in the form of potential threats to homeostasis – the information from this system may have survival value and may be given ‘priority’, enabling it to override the shutdown state. Activation at the level of the insula also allows for the formation of a mental image – the subjective awareness of the noxious stimulus – thereby facilitating a shift in focus-of-attention to the present moment (see subsequent section).

In the re-experiencing PTSD scenario, patients can also use TRP channel activators to help them break out of the ‘flashback’ state. On the homeostatic sensory-reset hypothesis, ingestion of TRP channel activators when a patient is beginning to experience a flashback gives the homeostatic/interoceptive system a ‘jolt’, interrupting current processing and forcing the system to process information about the jolting stimulus. In this way, the somatosensory input from pungent foods feeds into the brain’s interoceptive/homeostatic system, activates it, and allows the system to reset itself – and associated neural networks – in a way that supports, once again, the individual’s subjective sense of connection to the environment and the here and now. As noted above, activation at the level of the insula also allows for the formation of a mental image – the subjective awareness of the jolting stimulus – allowing focus-of-attention to shift to the present moment, (see subsequent section). Interestingly, the current version of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) refers to the flashbacks that occur as part of the re-experiencing subtype of PTSD as ‘dissociative reactions’ because they involve a loss of connection to the present moment in response to reminders of the trauma, leading the individual to feel or act as if the traumatic event(s) were recurring (American Psychiatric Association, 2022).

We offer readers the following clinical example for a patient with re-experiencing PTSD.

A 70-year-old woman with a diagnosis of PTSD presented with frequent flashbacks and re-experiencing of past trauma. Following a recommendation to trial pickle juice during these episodes, the woman began keeping pickle juice in the refrigerator and consuming it in small amounts when experiencing flashbacks. She reported that this intervention has successfully halted her flashbacks each time it was used. In cases of more intense flashbacks or re-experiencing, she found that consuming up to three small glasses of pickle juice was necessary to effectively alleviate symptoms.

In sum, because PTSD involves a loss of balance in the somatosensory pathways (Kearney and Lanius, 2022), activation of these pathways via TRP channel activators – coupled with a reset of the interoceptive/homeostatic system – allows patients to utilise pungent foods to disrupt both forms of dissociation: those involving decreased top-down modulation (flashbacks and reenactment) and those involving increased top-down modulation (‘shutdown’ symptoms such as emotional numbness, spaciness, and derealization/depersonalization).

Use of smelling salts for homeostatic sensory reset

Neurologist Jon Stone of the University of Edinburgh asked if ‘there is a strong connection in all this [TRP channel activators, the somatosensory sensory system, and our hypothesis about a homeostatic reset in that system] to smelling salts for swooning – which when prolonged has always been functional’ (Email communication, 13 January 2026). He suggested that it would be very helpful if we the authors were able to ‘sort out neurobiology of smelling salts!’ (Email communication, 14 January 2026).

In response to Jon’s challenge, we undertook an interesting journey of discovery. The short answer to Jon’s question is yes. Yes, because ammonia does activate TRP channels that sit in the nose and are part of the trigeminal chemosensory system. These TRP channels are typically located on the nerve endings of trigeminal polymodal nociceptor neurons whose cell bodies sit in the trigeminal ganglion. The information is carried via the trigeminal nerve (fifth cranial nerve) to the medulla oblongata in the brainstem, where it is relayed and joins the same interoceptive/homeostatic system we have described for pungent food (see Figure 2, further below). In this way, ammonia, like pungent foods, can activate the homeostatic integrating centres from the brainstem to the insula and limbic cortex to initiate a homeostatic reset. Ammonia does so by activating TRP channels in the nose, and pungent foods do so by activating TRP channels in the gastrointestinal track. For individuals who use ammonia salts for the management of dissociative states, the reset of the interoceptive/homeostatic system supports, once again, the individual’s subjective sense of connection to the body, emotional self, and environment. The long answer to Jon’s question is provided below.OPEN IN VIEWER

‘Ammonia is a noxious volatile chemical and is commonly encountered in household cleansers, artificial fertilizers, industrial pollutants, and in human and animal waste. Exposure to ammonia … elicits a distinctive pungent sensation in the nose’ (p. 153) (Dhaka et al., 2009). Most of us are familiar with this pungent sensation. Smelling salts are ammonia-based products used to prevent fainting or to revive someone who has fainted. They go back to the thirteenth century – or even earlier – and were at one time a staple of the doctor’s medicine bag (Richardson, 2019). ‘In the 17th century chemists obtained ammonium carbonate by crystallizing an aqueous solution of ammonia that was obtained through the distillation of horn and hoof shavings from harts (male red deer). The carbonate was initially called “spirits of hartshorn.” The addition of perfume to the ammonium carbonate resulted in a preparation that became known as smelling salts’ (Britannica, nd). In the 1800s, because of Queen Victoria’s interest in English lavender, salts of lavender became a popular choice (Museum, 2022). In Victorian Britain, smelling salts were carried around by upper-class women in decorative containers called vinaigrettes, ¹ which held sponges infused with the smelling salts (Britannica, nd; Museum, 2022). Their popularity was related, in large part, to the fashion of restrictive corsets, within which women were often laced so tightly that diaphragmatic breathing was restricted, leading to faintness (see Text Box 1) (Isaac, 2017; Museum, 2022). The problem was sufficiently widespread that it was common for police constables to carry a container of smelling salt (Museum, 2022).

Text Box 1. The corset

According to the fashion historian Kass McGann, corsets have gone through many iterations. The ‘first surviving historical object we can reasonably call a “corset” … [is] the funerary garments of Eleanora of Toledo, Duchess of Florence’. Its function was, she says, as a foundation for the elaborate gown worn over it rather than ‘to form the body in a way that was unnatural’. It was in the seventeenth century that heavy boning came into bodices and ‘only with the development of metal eyelets in the 1830s where corsets became tight-laced’ (quoted from Guardian article by Ellie Violet Bramley (2024)). The Lancet and Edinburgh Medical Journal published a number of articles about the health risks associated with the corset, including death from syncope (Lancet, 1890), displacement of ribs and internal organs (Symington, 1892), and inability to breath using the diaphragm (Fish, 1909).

According to Bramley (2024), a 2017 Charleston Museum exhibit, and a New York Times fashion column, the trend of wearing corsets is coming back into fashion (Friedman, 2026).

Olfactory system

The extended olfactory system includes the olfactory epithelium (olfactory sensory neurons in the nasal mucosa), the septal organ (a small patch of specialised olfactory sensory epithelium), and the vomeronasal organ (specialised in detecting pheromones). The olfactory sensory neurons have cilia – olfactory hairs – that sit on the surface of the nasal mucosa and react to odours to stimulate the olfactory receptor neurons and axons that make up the first cranial nerve and project directly to the olfactory bulb in the forebrain. The olfactory bulb sends projections to the primary olfactory cortex (including piriform cortex and corticomedial amygdala). The primary olfactory cortex, in turn, sends projections to the thalamus and hypothalamus, medial amygdala and hippocampus, and orbitofrontal cortex and insula. In this way, information about odorants reaches a variety of brain regions and brain networks, allowing olfactory cues to influence homeostatic, visceral, emotional, and cognitive responses and behaviours (Martial et al., 2023; Purves, 2001a). The scented oils that are added to smelling salts – lavender, lemon, nutmeg, or eucalyptus – activate this system (Fung et al., 2021). More broadly, substances used in aromatherapy also activate this system (Cui et al., 2022).

Trigeminal chemosensory system (trigeminal polymodal nociceptor neurons)

Trigeminal polymodal nociceptive neurons have nerve endings that sit in the nasal epithelium, cell bodies that sit in the trigeminal ganglion, and axons that run in the trigeminal nerve (cranial nerve V) and terminate in the trigeminal nuclei located in the medulla oblongata (Purves, 2001b). The trigeminal ganglion is, in the head (the cranial nerve system), the equivalent of the dorsal root ganglia for the rest of the body (the spinal nerve system). Because TRP channels sensitive to ammonia have been demonstrated in dorsal root ganglia neurons (Dhaka et al., 2009), it is assumed that the same TRP channels are found in trigeminal polymodal nociceptive neurons. Thus, free ammonia that enters the nose activates TRP channels located on the free nerve endings of trigeminal polymodal nociceptive neurons. TRP channels convert the stimulus into action potentials, which are then transmitted in sensory trigeminal nerve fibres to trigeminal nuclei in the medulla and, from there, to the ascending pathway of the interoceptive/homeostatic system (see Figure 2) (Craig, 2002). Trigeminal polymodal nociceptive neurons detect, in addition to ammonia, a broad range of other irritants. In the nose these irritants are experienced as homeostatic feelings: burning, stinging, itching, tickling, cooling, warming, pungent, perception of atmospheric humidity, and so on (Brand, 2006).

Trigeminal chemosensory system (solitary chemosensory cells)

Solitary chemosensory cells (SCCs) are sentinel cells that sit in the nasal epithelium. These cells detect other classes of odorous irritants – including molecules produced by bacteria – ‘that are impermeable to epithelial tight junctions, and therefore unable to reach the trigeminal nerve fibers’ described above (p. 2 of 15) (Xi et al., 2023). Solitary chemosensory cells are innervated by trigeminal nerve fibres that relay information to the central nervous system, possibly into the ascending pathway of the interoceptive/homeostatic system. They can also trigger the release of neuropeptides into the nasal mucosa, evoking protective reflexes and pro-inflammatory responses (Xi et al., 2023 #17399).

The vomeronasal (Jacobson’s) organ

The vomeronasal (Jacobson’s) organ is a specialised chemosensory organ in the nasal septum of many vertebrates that detects pheromones and non-volatile chemical cues to trigger innate social, reproductive, and defense behaviours. It acts independently of the main olfactory system, sending signals to the accessory olfactory bulb and hypothalamus. The vomeronasal system is nonfunctional in humans. In the human embryo, the organ develops, and some of its cells migrate toward the hypothalamus. The organ then regresses, and the neural connections disappear (Trotier, 2011).

Protective reflex

The first response is a breath-hold coupled with a withdrawal reflex of the head or body to minimise inhalation and move away from the irritant stimulus (Bender and Popkin, 2024). The breath-hold is followed by a forced exhalation to clear the nasal passage (Bender and Popkin, 2024; Britannica, nd; Dhaka et al., 2009).

Increase in heart rate

The withdrawal reflex is associated with an increase in heart rate (Perry et al., 2016). The increase in heart rate is sympathetically mediated and generated from the brainstem.

Homeostatic emotion (sensation of the irritant)

The stimulus information continues to ascend along the pathway of the interoceptive/homeostatic system (see Figure 2), reaching the insula, where the subjective awareness of the ‘sting’ of ammonia captures focus-of-attention to the present moment: the unpleasant sensation of ammonia.

Homeostatic reset of the brain’s interoceptive/homeostatic system

Our sensory-reset hypothesis posits that ammonia – in the same way as pungent foods – overrides the decrease in sensory information that is part of shutdown dissociative states and resets the central circuitry that modulates processing within the brain’s interoceptive/homeostatic system and associated networks.

Vasodilation of cerebral arteries

Ammonia inhalation has been shown to cause an increase in cerebral vascular conductance (a dilation of cerebral arteries) with an actual increase in blood flow in the middle cerebral artery, which is coupled to a sympathetically mediated increase in peripheral vascular resistance (a vasoconstriction of arteries in trunk and limbs) (Perry et al., 2016). These two vascular events essentially contribute to a redistribution and increase in blood flow to the brain, which will make the subject more alert. Interestingly, no significant increase in blood pressure has been reported (Perry et al., 2016). A more direct effect of ammonia on the cerebral vasculature after absorption in the blood stream has been proposed but has not been verified (Andersson et al., 1981; Chodobski et al., 1986; Perry et al., 2016).

Pickle juice and other pungent foods as a strong distractor

A number of physicians commented on the use of pickle juice and other pungent foods as a distraction mechanism. Jon Stone, the neurologist, wrote, ‘It makes sense to use a strong distractor. We need practical ideas like this’ (Email communication, 13 January 2026). And Gaston Baslet, a Harvard Medical School neuropsychiatrist, wrote ‘While the biological explanation is hypothetical, I think that sensory stimulation as a way to reset attention, top-down resources that breaks symptoms (even temporarily) is a plausible mechanism’ (Email communication, 14 January 2026).

Here we note that the interoceptive/homeostatic system that processes information about pungent foods is the same system that processes information about pain, itch, temperature, pH (potential of hydrogen), and other homeostatic information about body state. The idea that ‘pain interrupts and demands attention’ was put forward by Chris Eccleston and Geert Crombez in 1999 in a landmark article, ‘Pain Demands Attention: A Cognitive-Affective Model of the Interruptive Function of Pain’ (p. 356) (Eccleston and Crombez, 1999). But as we all know, any of these stimuli, when they are unpleasant, irritating, or jolting in some way, demand attention. In the above article the authors defined attention in the following way

Attention is defined as selection for action. Intrinsic to the selection of pain is the urge to escape … The selection of pain interrupts attention, ruptures behavior, and imposes a new action priority to escape. (p. 356)

At that time (in 1999), A. D. (Bud) Craig, an anatomist and neuroscientist whose groundbreaking work at the Barrow Neurological Institute was to advance our ‘understanding of the neuroanatomical basis of the bodily self, emotion, and subjective time’, had only just begun his life-long work (p. 1) (Strigo et al., 2025). In time, Craig was to map an ascending neural pathway for homeostatic information from the body to the brain, determining that in the brain of primates (including humans), the insular cortex was responsible for making representations of these elemental feelings, with the anterior insular enabling for subjective representations (mental images) of the physiological condition of the body (see also previous section) (Craig, 2002; Craig, 2013a). In this way, we not only respond to homeostatic information implicitly and automatically, but we also hold a mental image of the physiological condition of the body and are therefore aware of the feeling of pain, itch, the sensation caused by pungent foods and irritants (like ammonia), and so on. And when the stimulus is unpleasant or salient in some other way, our attention is ‘caught’ by these stimuli.

These homeostatic feelings from the body (in the insular cortex) are ‘conjoined with homeostatic motivations that guide adaptive behaviours (in the cingulate cortex)’ (Strigo and Craig, 2016). The cingulate cortex guides both implicit/autonomic/non-voluntary behaviours and conscious explicit/voluntary behaviours (Pearson et al., 2011). Put simply, homeostatic feelings are the perceptual correlate of a behavioural motivation (Craig, 2013a).

The above-described understanding of the interoceptive/homeostatic system helps us answer Stone’s and Baslet’s question about pungent foods – and also ammonia – as a distractor. When homeostatic feelings signal danger or potential danger, they capture attention and shift focus-of-attention to the here and now, thereby enabling conscious decision-making to be recruited into the action-response process. Thus, the individual can replace the lid on the offending cleaning agent and don a protective face mask to minimise inhalation fumes whilst proceeding with the task of cleaning. It is important to note, however, that at this point in the process – when homeostatic feelings become conscious – automatic responses such as protective reflexes, increase in arousal, and so on will already have been implemented by the nervous system, and, where relevant, the override of top-down over-modulation will have already occurred (see previous section on PTSD). In this manner, the ‘distractor’ element of the interoceptive/homeostatic response to irritants and other danger signals is just one component of a larger package of responses. In our view it is this larger package of responses to pungent foods, ammonia, and other irritants – the sum total of responses – that work together to enable disruption of states of dissociation.

The homeostatic sensory-reset hypothesis and the predictive-coding model of FND and dissociative disorders

In a new, 2026 article in Brain, Stanley Lyndon of Harvard Medical School (Lyndon, 2026) updates and expands the predictive-coding model of FND published by Mark Edwards and colleagues in 2012 (Edwards et al., 2012). The articulation of this new model, which includes both FND and dissociative symptoms, prompted us authors to consider how activation of the brain’s interoceptive/homeostatic system by pungent foods may potentially dovetail with the predictive-coding model of brain function.

As Lyndon explains, predictive coding

views the brain as a layered system that constantly compares prior predictions (expectations shaped by past experience) with incoming sensory signals, and shows how an unhelpful prediction can dominate perception and action when it is given too much weight or confidence (precision). Within this framework, predictions reflect the brain’s best estimate of current or impending states, while precision refers to the weighting assigned to those predictions relative to sensory feedback. (p. 2, Epub ahead of print) (Lyndon, 2026)

What Lyndon’s new model adds is to embed precision control within a four-level hierarchy – affective, interoceptive, proprioceptive, and spinal. In this model, increases in arousal play a key role in ‘igniting’ surges in any combination of channels or symptom streams. The channels include motor, sensory, cognitive, and visceral symptoms that are commonly seen, in various combinations, in patients with functional and dissociative disorders.

Using this elaborated predictive-coding model, Lydon postulates that ‘when autonomic arousal crosses a channel-specific threshold, the system can briefly overtrust whatever prediction is active at that moment, producing a rapid surge in precision that can momentarily flood the system and lock a symptom into place’ (pp. 5–6, Epub ahead of print). In other words, ‘autonomic arousal can temporarily increase the brain’s confidence in its own predictions faster than sensory feedback can correct them’ (p. 6, Epub ahead of print). Over time, ‘as precision rises and falls, symptoms wax and wane, and selective focus can transiently shift precision weighting within the attended channel’ (p. 8, Epub ahead of print). According to the model, changes in focus-of-attention also shift confidence in predictions, thereby causing symptoms to amplify or wane. Attention to symptoms increases the brain’s confidence in the prediction (symptoms amplify), and attention away from symptoms decreases the brain’s confidence in the prediction (symptoms wane).

In this updated predictive-coding model, irritants and pungent foods would potentially recalibrate the brain’s predictive-coding system via two mechanisms. First, they provide a strong interoceptive signal that – akin to pain, temperature, acid, and inflammation (TRP channel activators) – represents a potential threat to homeostasis and cannot be dampened down and ignored. In this way, irritants and pungent foods may lead the brain to recalibrate the weight given to incoming sensory information, enabling it to update and potentially correct aberrant predictions. Second, as part of this same homeostatic process, the subjective awareness of the sensations produced by pungent foods – such as the burning ‘heat’ of chilli peppers, the ‘cooling effect’ of menthol, or the ‘bite’ of wasabi and other mustards – shifts the focus-of-attention and enables aberrant processes to wane.

What about aromatherapy?

As we noted earlier, in response to our article about the use of pungent foods as a grounding strategy to disrupt dissociative shutdown, Lucia Tesolin, the Peruvian neurologist, told us about a current study that is examining the use of olfactory stimuli in patients with functional/dissociative seizures (Tesolin, nd). In that study, patients trial a range of olfactory stimuli – palo santo (Bursera graveolens, a native tree,), galán de noche (night jasmin), eucalyptus, fresh coffee, cinnamon, anise, aromatic fruits (mango, guava, lime), and Amazonian fruits such as aguaje – and use them as olfactory stimuli and early self-regulation tools when dissociative symptoms begin to emerge, to avert the functional/dissociative seizure (Personal communication 2 March 2026). Tesolin’s comment raises the question as to the neurobiology of aromatherapy and its potential use in dissociative states (including functional/dissociative seizures).

Essential oils – also known as scented oils, volatile oils, volatile chemicals, or odour molecules – ‘are the naturally aromatic oily liquids produced by plants, which are responsible for their essence or odor … [They] can be extracted from different parts of plants, including their leaves, barks, flowers, buds, seeds, and peels … [They] are a concentrated hydrophobic mixture of hydrocarbon volatile compounds that easily evaporate at room temperatures … In most plants, the major components of [essential oils] are terpenoid and phenylpropanoid derivatives. Terpenoids are the main components (comprising approximately 80%), but phenylpropanoid provides the flavour and odour of the [essential oils]’ (pp. 1–2) (Sattayakhom et al., 2023). Essential oils in which the terpenoid component has been removed are called terpeneless essential oils (Gattefossé, 1993 [1937]).

Aromatherapy is the use of essential oils from plants as therapy for the purpose of provoking psychological or physiological responses to improve physical, mental, and spiritual well-being (National Cancer Institute, 2023; Schneider et al., 2019). The practice of using essential oils for healing – because of their antimicrobial, anti-inflammatory, antioxidant, analgesic, antispasmodic, and sedative properties – goes back to antiquity. Text Box 5 provides a brief summary of the historical use of substances with olfactory qualities – including essential oils – in Greco-Roman, Byzantine, and Arabic medicine, with a particular emphasis on FND. The term aromatherapy is of more recent origin. It was coined by Maurice Gattefossé, who, in the early 1900s, worked as a chemist in a family-owned perfume company in France (Gattefossé, 1993 [1937]).

Text Box 5. A historical perspective on the use of essential oils for the treatment of functional symptoms

Historian Helen King describes how, in the texts of the Hippocratic corpus (450–250 BC), some of the writers conceptualised female medical problems – including a range of functional symptoms such as functional/dissociative seizures – as being caused by the movement of the womb (Helen, 2024). In this conceptualisation the womb would end up at some deviant destination in the body, resulting in suffocation (suffocation of the womb) and a range of associated physical symptoms. Substances with olfactory qualities were often used to treat this condition. ‘The pattern [was] usually that fragrant substances [were] applied to the vulva, in order to attract the womb back, while foul-smelling substances are placed under the nostrils to drive the womb away from the upper parts of the body’ (p. 21). Fragrant substances included various essential oils, whist foul-smelling substances included cabbage, garlic, onion, bitumen, and castoreum (from beaver caster sacs). ‘In addition – and in apparent contradiction – fragrant oils [could] be rubbed on the head and strong-smelling substances drunk, often in wine’ (p. 21).

Various versions of ‘scent therapy’ continued to be used across centuries in Greco-Roman medicine, Byzantine medicine, and Arabic medicine. Translation of texts from Arabia returned some of the classic knowledge back to Europe in eleventh and twelfth centuries, where it had been lost during the early Middle Ages (sometimes known as the Dark Ages).

Notwithstanding, not all knowledge was lost. A Latin manuscript from Western Europe from the eighth and ninth centuries – titled ‘De causis feminarum [On the Causes of Women]’ gave ‘practical advice on what to do “si vulva suffocantur” [if the womb is suffocated] … The patient should be given burned and pulverized stag’s horn in wine’ (p. 54) (Helen, 2024). At that time, burned and pulverized stag’s horn was a source of ammonia salts (see ammonia salts section).

The use of essential oils continued into the twentieth century. In his 1937 book about aromatherapy, René-Maurice Gattefossé made reference to various plant extracts for the treatment of functional/dissociative seizures. In his discussion of asafoetida – a gum extract from the roots of the ferula plant common in Central Asia – Gattefossé reports ‘serious attacks of [functional/dissociative seizures ² ] can be greatly helped by inhalation of the essential oil, stopping attacks almost immediately’ (p. 30). Asafoetida has a pungent, unpleasant odour and is used in small amounts as a garlic-and-onion substitute or to add an umami flavour to food. Gattefossé also notes that other clinicians report the use of pleasant-smelling scents for the same ailment: ‘the odours given off by heliotrope and vanilla are antispasmodic and help sooth emotional manifestations of varying degrees of gravity, commonly known as [functional dissociative seizures ³ ]’ (p. 69).

Conclusion

We conclude by thanking those who wrote to us asking questions and initiating what proved to be such engaging conversations about the neurobiology of pungent foods, ammonia salts, and aromatherapy – including the role of mental representations and focus-of-attention. We are grateful to our readers for challenging us to expand our analysis and consider so many new scientific and clinical issues.

As noted by the neurologist Jon Stone, we clinicians need a range of practical ideas – such as those discussed above – to provide our patients with options as to how they manage dissociative states (including functional-dissociative seizures), panic, dysregulation, anxiety, states of high arousal, or distressing memories that may arise because of past trauma. Being able to offer suggestions for strategies that harness the body’s own regulatory systems, which patients can trial and experiment with, allows for a broader range of options for everyone involved in the healing process.