Smelling potatoes when no potatoes are around is a form of phantosmia, the medical term for perceiving an odor without any external source. The experience is more common than most people realize, and the causes range from something as benign as a lingering cold to something that deserves prompt medical attention. What makes the potato smell particularly interesting is that it sits at a crossroads of real chemistry and brain misfiring, so sorting out whether the smell is genuinely there or entirely invented by your nervous system is the first practical step.
What Phantosmia Actually Is
Phantosmia means smelling something that is not physically present. It is distinct from parosmia, where a real odor is present but your brain distorts it into something different, like coffee suddenly smelling like sewage. With phantosmia, there is no odor source at all; the signal originates somewhere along the chain from the nose’s smell receptors to the brain’s olfactory processing centers.1PubMed Central. Parosmia and Phantosmia: Managing Quality Disorders Some people with reduced smell sensitivity also experience both parosmia and phantosmia together, which can make it harder to tell what is real and what is not.2PubMed Central. Prevalence and correlates of parosmia and phantosmia among smell disorders
Phantom smells can be pleasant, neutral, or deeply unpleasant. People describe smelling burnt toast, cigarette smoke, chemicals, rotting food, and yes, potatoes. The smell may be constant or arrive in episodes lasting minutes to hours. Some people notice it more at night or when they change position. The important thing to understand is that phantosmia is a symptom, not a diagnosis. It tells you something is going on, but not what.
Why Potatoes Specifically
If you are genuinely smelling potatoes and wondering whether something in your environment could be causing it, there is an answer worth knowing. Certain bacteria produce compounds called alkyl-methoxypyrazines that smell strikingly like raw potatoes. Researchers identified these chemicals in cultures of bacteria from the Serratia and Cedecea families, organisms that can colonize damp surfaces, drains, and even the nasal passages.3PubMed Central. Pyrazines responsible for the potatolike odor produced by some Serratia and Cedecea strains So before assuming your brain is inventing the smell, it is worth checking whether there is a bacterial source nearby: a damp cloth, a poorly sealed drain, or even an infection in your sinuses.
If you have ruled out a physical source and the potato smell keeps returning, you are more likely dealing with true phantosmia. The brain’s olfactory system can latch onto specific smell templates when it misfires, and starchy or earthy odors like potatoes are among the commonly reported phantom smells. The particular odor a person perceives often stays consistent across episodes, which suggests the misfiring follows the same neural pathway each time rather than randomly sampling from the brain’s full odor library.
Viral Infections and the Smell System
The single biggest driver of phantosmia awareness in recent years has been COVID-19. In a large survey of people with COVID-related smell disorders, about 37% reported phantom smells. Women were more likely to experience them, and the prevalence rose sharply during the first two months of illness before plateauing, with no decrease over 15 months of follow-up.4PubMed Central. Phantom smells: a prevalent COVID-19 symptom that progressively sets in A separate study of people with chronic COVID-related smell dysfunction found that phantom smells were the single most common qualitative complaint, reported by roughly 59% of participants. The smells described included rotten or putrid odors, cigarette smoke, and burnt rubber.5Journal of Allergy and Clinical Immunology. Clinical characteristics and predictors of recovery in chronic COVID-19 chemosensory dysfunction
COVID did not invent post-viral phantosmia, though. The common cold, influenza, and other upper respiratory viruses have caused the same problem for decades. The leading explanation involves what happens when the virus damages olfactory neurons in the nose. These neurons regenerate, but they do not always reconnect to the right targets in the brain’s olfactory bulb. This “miswiring” hypothesis, first described in the late 1970s, fits the timeline: many cases of phantosmia and parosmia appear about 45 to 60 days after the acute infection, roughly the period needed for olfactory neurons to regrow. Animal studies have confirmed that cutting the olfactory nerve disrupts the normal odor map, causing axons to project to wrong targets.6PubMed Central. Post-viral olfactory loss and parosmia
If your phantom potato smell started a few weeks to a couple of months after a bad cold or a bout of COVID, miswired olfactory neurons are a strong candidate. Many of these cases improve over time as the neurons continue to remodel, though recovery can take months or, in some cases, more than a year.
Neurological Causes
Phantom smells can also originate in the brain itself rather than in the nasal lining. Several neurological conditions are known to produce them, and the specific condition matters because it changes what you should do about it.
Epilepsy is one of the better-documented associations. Olfactory hallucinations were reported by 55% of patients with a form of epilepsy called transient epileptic amnesia in one study, and the experience often occurs as part of a seizure aura, the warning phase that precedes a seizure.7PubMed Central. On the nose: olfactory disturbances in Transient Epileptic Amnesia If phantom smells are brief, stereotyped (always the same), and sometimes followed by confusion, altered awareness, or involuntary movements, an epileptic cause should be investigated.
Migraine is another trigger. Olfactory hallucinations can serve as a migraine aura, with the smell arriving before the headache begins. In one clinical series, the smell episodes typically lasted 3 to 10 minutes and the type of smell remained the same across attacks for most patients.8PubMed. Scent of aura? Clinical features of olfactory hallucinations during a migraine attack (OHM) The onset of the olfactory aura varied from sudden to gradual, and some patients experienced it with only a fraction of their migraine episodes. At least one documented case involved a patient whose migraines were preceded exclusively by olfactory hallucinations with no visual or sensory aura at all.9PubMed. Migraine With Exclusive Olfactory Aura: Case Report and Literature Review If you get headaches and also smell things that are not there, the two could be linked even if they do not always occur together.
Parkinson’s disease is associated with olfactory hallucinations as well, though the reported frequency varies widely, from under 1% to about 18% of patients depending on the study.10MDPI (Neurology International). Phantosmia in Parkinson’s Disease: A Systematic Review of the Phenomenology of Olfactory Hallucinations Loss of smell is already recognized as an early sign of Parkinson’s, and phantosmia may be part of the same progressive olfactory decline.
Head injuries can damage the delicate olfactory nerves where they pass through the base of the skull. Clinicians at one specialty center evaluated over 200 patients with smell loss and phantosmia following head trauma and linked the changes to disruptions in growth factors that maintain olfactory function along with changes in brain neurotransmitters.11The FASEB Journal. Smell Loss and Onset of Phantosmia are Critical Aspects of Head Injury Cognition
In rare instances, phantosmia can be the presenting symptom of a brain tumor. One case report described a previously healthy 70-year-old woman whose first symptoms were phantom smells and a distorted sense of taste; imaging revealed a glioblastoma. The authors stressed the importance of recognizing phantosmia’s potential connection to seizure auras and the need for imaging to rule out structural causes like tumors or infections.12PubMed Central. Phantosmia and dysgeusia as the first presentation of glioblastoma This is uncommon, but it is the reason persistent unexplained phantom smells should not simply be ignored.
Sinus and Nasal Infections
Sometimes the problem is not in the brain but right inside the nose. Bacterial infections of the nasal passages or sinuses can directly stimulate or irritate the olfactory epithelium, the patch of tissue high in the nasal cavity where smell receptors live. One well-documented case involved an 82-year-old man who had been experiencing phantom smells for years, worse at night, with an ammonia-like quality. He found that moving his head could briefly relieve the smell. The cause turned out to be a Pseudomonas stutzeri infection inside his nose, and the phantosmia resolved completely after antibiotic treatment.13PubMed Central. A case study of phantosmia cured by antibiotic treatment of an intranasal Pseudomonas stutzeri infection
This case is worth highlighting because it represents a curable cause. Chronic sinusitis, nasal polyps, and lingering low-grade infections can all produce phantom or distorted smells. If the smell changes with head position, worsens when you lie down, or is accompanied by nasal congestion or postnasal drip, a visit to an ENT specialist to look for a treatable nasal cause is a sensible move.
Medications and Polypharmacy
A surprisingly overlooked cause of phantom smells is medication. A study using nationally representative US health data found that people taking five or more prescription medications had about 69% higher odds of reporting phantom odors compared with people taking fewer drugs. Nine specific drug classes showed a statistically significant association with phantom smells, including cholesterol-lowering drugs, antidepressants, pain medications, diabetes drugs, proton pump inhibitors, anticonvulsants, calcium channel blockers, sedatives, and muscle relaxants.14PubMed Central. Prescription Medication Use and Phantom Odor Perception Among US Adults
Among adults 60 and older, the associations were even stronger. Diabetes medications, cholesterol drugs, and proton pump inhibitors were each associated with roughly 74% to 88% greater odds of phantom odor perception in that age group.14PubMed Central. Prescription Medication Use and Phantom Odor Perception Among US Adults This does not prove the medications directly cause the phantom smells, since people who take many medications also tend to have more health conditions. But it does mean that if you started noticing a phantom potato smell around the same time you began a new medication, it is worth raising with your doctor.
Psychiatric and Anxiety-Related Causes
Olfactory hallucinations are not exclusive to neurological disease. They appear across a range of psychiatric conditions. In one study, about 35% of patients with schizophrenia reported olfactory hallucinations, but so did 19% of patients with depression and 29% of patients with eating disorders.15PubMed. Olfactory hallucinations and olfactory identification ability in patients with schizophrenia and other psychiatric disorders The fact that depression and eating disorders showed notable rates challenges the common assumption that smelling things that are not there must mean psychosis.
Anxiety deserves specific mention. One case report described a 66-year-old woman with worsening phantom smells over four years who was ultimately diagnosed with generalized anxiety disorder. Her olfactory hallucinations disappeared after treatment with anti-anxiety medication.16PubMed Central. First-episode olfactory hallucination in a patient with anxiety disorder: A case report That is a single case, but it illustrates an underappreciated pathway: chronic anxiety can alter sensory processing enough to produce phantom perceptions, and treating the underlying anxiety can resolve the smell.
Chemical Exposures at Work
If you work around industrial chemicals, there is another possibility to consider. Long-term occupational exposure to certain substances has been linked to olfactory dysfunction, including distorted or phantom smells. Metal compounds involving cadmium, chromium, and nickel, along with formaldehyde, have the strongest evidence for damaging the sense of smell.17PubMed Central. Olfactory dysfunction revisited: a reappraisal of work-related olfactory dysfunction caused by chemicals The damage can show up as reduced smell, distorted smell, or phantom smells. If you have chronic chemical exposure at work and are noticing smells that do not seem to have a source, that context matters when talking to a doctor.
Who Gets Phantom Smells
Phantosmia is not evenly distributed across the population. A large US study found that women consistently reported phantom odors at higher rates than men across every age group. Among women in their 40s and 50s, roughly one in ten reported the experience, while rates among men peaked around 5% in the 60-to-69 age range. Interestingly, phantom odor reports among women actually declined somewhat after age 60, which is the opposite of what you might expect if age-related neurodegeneration were the main driver.18JAMA Otolaryngology–Head & Neck Surgery. Factors Associated With Phantom Odor Perception Among US Adults
The same study found a socioeconomic gradient: people with lower income-to-poverty ratios had about 60% to 65% higher odds of reporting phantom odors than those in the highest income group.18JAMA Otolaryngology–Head & Neck Surgery. Factors Associated With Phantom Odor Perception Among US Adults The reasons are not clear but could reflect differences in occupational exposures, access to care for conditions that cause phantosmia, or other health disparities.
A separate population-based study of older adults found a genetic component: carriers of a particular variant of the BDNF gene (a gene involved in nerve growth and repair) were more likely to experience phantom smells. People with phantosmia were also more likely to have parosmia, suggesting that the two conditions share overlapping mechanisms.19PubMed Central. Phantom Smells: Prevalence and Correlates in a Population-Based Sample of Older Adults
What Can Be Done About It
Treatment depends entirely on the cause. When phantosmia is driven by a nasal infection, antibiotics can resolve it entirely, as the Pseudomonas case described earlier demonstrated. When a structural cause like nasal polyps or a sinus mass is identified, surgical correction often helps.
For cases that persist without an identifiable or treatable cause, options become more limited but do exist. A review of the medical literature describes several approaches that have been used with success in small patient series. Topical application of a local anesthetic to the olfactory region of the nose can temporarily abolish the phantom smell, which also serves as a diagnostic test: if numbing the olfactory area kills the phantom smell, the problem is peripheral (in the nose) rather than central (in the brain). For patients with long-standing phantosmia that has not responded to medical management, surgical excision of the olfactory epithelium or cutting of the olfactory nerves has been reported to cure the condition.13PubMed Central. A case study of phantosmia cured by antibiotic treatment of an intranasal Pseudomonas stutzeri infection Surgery is a last resort since it permanently eliminates the sense of smell on that side, but for people who have lived with relentless phantom odors for years, it can be a worthwhile trade.
Post-viral phantosmia frequently improves with time as the olfactory system continues to remodel. Smell training, which involves deliberately sniffing a set of distinct scents for several minutes each day, is widely recommended for post-viral olfactory disorders. The rationale is that structured olfactory input helps guide regenerating neurons toward correct targets. If medications are the suspected trigger, adjusting doses or switching drug classes is worth discussing with a prescriber. And when anxiety or another psychiatric condition is the driver, treating the underlying condition can resolve the phantom smells, as the anxiety case above illustrates.
Migraine Auras and the Smell-Headache Connection
One scenario that catches people off guard is smelling something strange and then getting a headache an hour later, without ever connecting the two. Olfactory auras in migraine are underrecognized partly because visual auras (zigzag lines, blind spots) dominate the textbook descriptions. But olfactory hallucinations during migraine attacks do meet the formal criteria for a typical aura, and their characteristics are fairly consistent: the same smell tends to recur across attacks, onset can be sudden or gradual, and the episode usually resolves within 10 minutes, well before the headache peaks.8PubMed. Scent of aura? Clinical features of olfactory hallucinations during a migraine attack (OHM) Case reports also document migraine episodes preceded by olfactory symptoms alone, with the smell aura sometimes occurring without any headache at all.20PubMed Central. Various presentations of the olfactory hallucination in two patients with migraine disease: Case report
If your phantom potato smell arrives in discrete episodes, lasts a few minutes, and is sometimes followed by a headache or other migraine symptoms like light sensitivity or nausea, it may be worth keeping a diary to see whether the smell consistently predicts a migraine. Recognizing the pattern does not just explain the smell; it opens the door to migraine-preventive treatment that could reduce both the headaches and the phantom odor episodes.
When the Smell Comes and Goes With Your Hormonal Cycle
The finding that women report phantom smells at markedly higher rates than men, especially in the 40-to-59 age range, has led researchers to consider hormonal influences. That age window overlaps with perimenopause and menopause, when estrogen levels fluctuate and eventually decline. Estrogen is known to modulate olfactory sensitivity, and some women report heightened or altered smell perception during pregnancy, around ovulation, or during hormonal transitions. While no large trial has directly tested whether hormone replacement therapy resolves phantosmia, the demographic pattern suggests hormonal changes may lower the threshold for olfactory misfiring in some women. If your phantom smells started or worsened during a hormonal transition and other causes have been ruled out, this context may be worth raising with your doctor, even though the research here is still circumstantial.