Can We Smell Diseases: An Interesting Correlation Between Illness and Odor

You probably didn’t know this, but research shows that human beings can smell diseases.

Most research conducted regarding smells usually involve mice and rats. Consequently, the sense of smell in human beings has been the last in the scorecard of senses.

However, a recent study in the area disproves of the belief of the 19th-century scientists that the sense of smell is weaker than any other senses. A study published by Swedish Researchers from Karolinska Institute, Sweden, suggests that one can smell when another person is ill.

Scientists who study volatile organic compounds (VOCs) have long established that each has a distinct odor. In that, we have an “odorprint” that is unique as one’s fingerprint. Your smell escapes from the skin, urine, breathe, and blood.

Your body smell emanates from compounds that depend on your diet, age, sex, metabolism and most importantly, your health. As you consider an Australian medical residency, go through this article to gain more insight on the sense of smell in humans.

Does Infection modify one’s body odor?

One’s body odor is a complex combination of variable compounds. Microbes in our bodies play a role in how we smell. When pathogens invade our bodies, they change the level and type of these bacteria which leads to adjustment of one’s body odor.

Once your immune system is activated to respond to the pathogens, it changes the metabolic byproducts from the hormonal and endocrine systems. Also, in mice, their odor and mating preferences are influenced by genes that control one’s body immune system.

An experimental psychologist at the Karolinska Institute, Matt Olsson, stated that our smells become more aversive when we fall sick. Different diseases may be having distinct smells, e.g.

  • Diabetes smells like rotten apples due to the release of low levels of acetone in the breath
  • People with typhoid fever are reported to smell like baked bread
  • Scrofula leaves the infected smelling like stale beer, etc.

All these subtle scents were likely picked up by a trained nose. The Olsson’s team set out to explore the way odors reveal when one is recently infected or is sick. The study further showed that people prefer and are more willing to socialize with healthy people as compared to ill individuals.

In a recent study conducted by the team, revealed that when one smelled an unpleasant odor, the disgust that they feel activates a mild immune reaction of their own. There is an increase in immune activity, as the body gears up for an attack.

It is a way for the body to protect the individual from a further disease. Olsson further states that “Emotional disgust is there to keep us healthy.”

In addition to the research, researchers have also reported a Scottish woman who can smell Parkinson’s disease by its scent. In a particular case, it was several months before the disease was diagnosed.

What does your Body Odor say about You?

A mosquito magnet

Have you ever experienced a situation in summer where you get bitten by mosquitoes, more often than others even though you were exposed to the same conditions? It is probably because your genetic composition attracts mosquitoes.

A study by researchers that involved identical and fraternal twins who were exposed to mosquitoes shows that:

– Identical twins got equal number of bites

– Fraternal twins had differing number of bites from the mosquitoes. The mosquitoes tend to prefer one over the other.

The scientists believe that the genes that contribute to one’s body odor could affect why mosquitoes prefer one individual over another.

Sensitive animals can smell fear, stress, etc.

You have probably watched a movie or documentaries on how dogs are used to catch a criminal, as you take a medical residency in UK, break. Maybe the culprit ducks into a crowd and everyone is running for safety; a dog can smell fear and also follow your odor.

When you have stress from home or even work, other people may not detect it from your odor but sensitive animals can. It doesn’t modify your smell, but it adds to it.

Healthy or Not

As per the study by the Karolinska Institute, research shows that different diseases have a distinct smell. The response by the immune system to fight off the infection leads to an addition to your body odor. In a study published by European Urology, a specific dog was trained to identify cancer in patients.

It was able to identify 30 out of the 33 prostate cancer patients correctly. Earlier in the article, we touched on the presumed smells for certain diseases that a trained human nose could detect. For example, diabetic patients smelled like rotten apples, etc.


Theoretically, human beings can distinguish tens of millions of distinct smells and maybe more. However, scientists are working towards being able to use one’s odor for faster and accurate diagnosis of diseases than the technology being in use, currently.

Think about this as you work on your residency application personal statement. With a breakthrough in studies in the area, we will be able to detect and avoid contracting diseases from the infected, just by the sense of smell.

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Jame Rop

Jame Rop is a content-writer and an amateur guest post writer. His dream is to open animal shelter and make all the homeless dogs and cats happy. His life motto is “Remember that Life is a one way ticket”. He travels a lot, likes extreme and sport.