What are Olfactory Hallucinations?

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  • Written By: Mary McMahon
  • Edited By: O. Wallace
  • Last Modified Date: 09 December 2018
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Olfactory hallucinations are a type of hallucination which involves the olfactory system. Patients who experience olfactory hallucinations think that they are smelling something when there is nothing in the environment producing the odor being experienced. They may be able to describe the smell in detail, and they can have reactions to the smell, such as gagging at the smell of feces or increased saliva production at the smell of chocolate chip cookies. Although phantosmia, as it is known to the medical community, may seem primarily like an interesting curiosity, it can actually be a sign that a patient has a severe medical problem, and people who smell things which don't exist definitely need to see a doctor.

One of the most common causes for these hallucinations is brain damage. The olfactory system is a physical sensory system, just like the systems used to allow people to perceive touch and vision, and damage to that system can interfere with its function. People with tumors or severe head injuries can start to smell phantom odors as a result of confused neurons along the sensory system's pathways.


Phantosmia can also be a symptom of epilepsy, caused by temporal lobe seizures which trigger the brain into thinking that a smell is present. Some people with migraines have also described hallucinations related to smell during the aura phase before a migraine sets in. Other causes of olfactory hallucinations include exposure to certain toxins, some types of drugs, and physical damage to the olfactory system, such as an infection.

Some psychiatric conditions have also been linked with phantom odors. People with severe psychiatric disorders may have profound chemical imbalances in their brains which trigger the chemosensory system which allows people to perceive smell, creating a hallucinatory experience.

The smells experienced can be good or bad, with more people tending to report strong or unpleasant odors. Olfactory hallucinations should not be confused with parosmia, in which a smell is not processed correctly by the brain, causing the smell to change in the perception of a nose's owner. In an example of parosmia, someone might smell a rose and complain that it smells like rust, smoke, tar, or something else. In this case, a smell is present and being perceived, but it's not being perceived properly.

People who experience olfactory hallucinations should consult a neurologist or psychiatrist who can determine the cause and make treatment recommendations. Diagnosis may include the use of medical imaging to look at the brain and the olfactory system for signs of abnormalities.


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Post 17

I often smell burnt sugar, which is not really unpleasant. Once I have checked to make sure that nothing is really burning, it just sort of amuses me. Since this has been going on for years, without getting more intense, I don't suspect brain damage, and if it's psychological I'm okay with it.

Post 15

I keep smelling tobacco, but I don't smoke and live alone. Someone was smoking in my house a few days ago but I thought it had cleared. I emptied bins and stuff, but the smell lingers. I keep thinking I am imagining this.

Post 13

I feel so guilty about taking too many prescriptions that once in a while I try to stop them. If I stop too suddenly I experience the "bad metal burning" smell. I really believe it is a chemical imbalance. I really hope it isn't brain damage though!

Post 12

I, too, have suffered from olfactory hallucinations for nearly all of 2012; the constant smell was like burning plastic. I had to wear a surgical mask when watching TV and could not stand to be around computer equipment or even computerized cash registers in stores. I had EEGs and was prescribed anti-seizure medication which did not help. In the middle of last year, I noticed heavy yellow mucus from my nostrils - very different from a runny nose due to summer allergies - and asked my neurologist for a referral to an ENT specialist because I felt something was wrong with my sinuses. He could not find anything but prescribed a saline solution to rinse the nasal cavities.

I used this for

two or three months and after another month, the smell of burning plastic was gone. Whatever the reason was and is for other sufferers of olfactory hallucinations, I suggest they have their sinuses checked. It certainly helped in my case.
Post 11

I have been smelling cinnamon since I woke up this morning. I still smell it now. Reading this site now makes me nervous.

Post 10

My mother complained of a strange smell. She described it as burnt metal. After consulting her doctor she was immediately sent to hospital with a very high blood pressure (over 210).No previous history. The olfactory hallucination was a result of pressure on the brain. A brain scan and ECG showed no damage and she was treated with Amlodipine. I'm glad she didn't ignore the signs.

If you are experiencing any of these symptoms or know of someone who is, be sure to consult a professional.

Post 9

I just found this because I was smelling chocolate chip cookies when there are none baking. I have never had an olfactory hallucination before, but this article freaked me out.

Post 8

@ post 6: You're smelling the cigarette paper. During the process of manufacturing the paper there are chemicals used. Sometimes due to machine malfunction some paper absorbs too much. This gives it the smell. Cigarettes are rolled with a bare minimum of paper so they rarely emit that smell.

Rolling papers sold commercially are cut in larger "sheets" so the taste and smell is much more evident. The cigarettes you can't do anything about, but rolling anything else you can try vegetable oil based sheets. They are not as common but they don't have the chemicals and you can actually taste the stuff.

Post 7

I looked up olfactory hallucinations because frequently, while watching TV or just being out and about I have them. If I see someone in a car light a cigarette, I smell it, even though there's no way I actually could. This morning, on TV, I saw a man step in a pile of cow manure in a barn and I smelled the whole thing - hay and dung alike.

Usually it's smoke or other random things, not food. I don't think I'm epileptic, nor do I think I have a brain tumor. I just smell things that aren't there!

Post 6

One time I was smoking a regular cigarette and thought I was smoking a doobie because it smelled like it but I didn't get high. I don't know why it smelled like it. It was either really bad pot or else I imagined it because I smoke so much of it but this article didn't explain why that would happen.

Post 4

This reminds me of a Harry Potter quote, and I think if you threw olfactory hallucinations into it, it would go something like this.

"Even in the wizarding world, hearing voices (and smelling smells) that aren't there is a very bad sign." Not only is it among the fairly common schizophrenic symptoms recognized by doctors, it could otherwise be a sign of damage to your brain, your olfactory system, or even your other senses as well.

Post 3

Psychosis and hallucinations occur when someone is losing touch with reality. This can be due to an imbalanced mode of thinking which they have adopted, or a larger physical issue in the brain, such as a tumor or a harmful chemical imbalance. Regardless of cause, these issues can be harmful to self and possibly to others, and should not be taken lightly.

Post 2

Symptoms of schizophrenia include sensing things which are not present, responding to random stimuli, inexplicable fear and exhilaration, and muttering words which make little or no sense. If you are experiencing these symptoms or know of someone who is, be sure to consult a professional to have it taken care of.

Post 1

Auditory hallucinations can be worse than olfactory hallucinations, because they make you hear things that are not real. You might suspect that someone said something to you which they never really said, and you may hear voices. This can be scary and cause many negative effects. Most of the time, hallucinations such as these can be easily dismissed as a mis-hearing, but when it gets excessive and someone starts to take them seriously, they should contact a professional.

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