What Does Cancer Smell Like?

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The earlier cancer is detected and treated, the better your outlook. Researchers are always trying to find ways to detect cancer at an early stage. However, early detection can be challenging as some cancers only start to show symptoms at a very advanced stage. Researchers are currently exploring the possibility of detecting the odor of cancer to help reach a diagnosis sooner.

This article will review why cancer has an odor and how it can be detected. It will also discuss the impact of changes in body odors from cancer treatment. 

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It's well known that dogs have an incredible sense of smell. For years, humans have recruited dogs for their heightened sense of smell to sniff out drugs and weapons, and to aid in the search of missing people.

Researchers are now wondering if dogs might also be able to smell sniff out cancer in humans.

Studies have shown that dogs have the potential of smelling volatile organic compounds (VOCs) significantly better than humans. VOCs are byproducts of some biological processes in the body. Things like infection, inflammation, and even cancer, can produce VOCs, which can be sensed in the breath or urine.

In these studies, dogs were trained to detect the scent of cancer, often using breath or urine samples. Although it isn't exactly known which VOC in the cancer the dogs are able to smell, they've been successful in detecting cancer.

In one study, dogs were provided with urine and breath samples. Dogs with access to both urine and breath samples were able to correctly detect cancer in 98% of the samples. Dogs with access to urine samples alone were able to correctly identify 87% of samples with cancers, and dogs with access to just breath samples, correctly identified cancer in 78% of the samples.

It's important to note, however, that the study doesn't mention whether the dog identified VOCs in people without cancer.

What Causes Cancer Smells

Scientists are still trying to determine exactly what causes cancer to have a smell. Cancer is essentially a process in which cells don't divide properly (the cells multiply too quickly and don't die when they're supposed to). This abnormal process can lead to the death of other, healthy cells and changes in the body that may produce VOCs.

These VOCs can be detected in the breath and urine samples of people who have cancer, as well as in other body fluids. One study found that many VOCs were present at different levels for a variety of cancers, including breast, prostate, lung, and bladder to name a few. 

In the study, the levels of certain VOCs found in people with cancer were higher than those without cancer.

It’s important to note that there are no standard procedures to test for VOCs, nor has there been a proven clinical benefit to perform such tests.

One of the VOCs that may produce a scent is polyamine. This compound is often produced at higher levels in cells that are dividing quickly, which cancer cells do. Polyamines can be detected in the blood and urine of people with cancer.

If a cancer is close to the surface of the skin and has caused an ulcerated mass to form, this can become a breeding ground for bacteria. The infection that results can then cause a foul odor.

Treatment Odors

The average person is not able to detect the smell of cancer, but they may notice changes in the odor of body fluids when they're receiving treatment for cancer. 

The sense of smell may be more sensitive to people undergoing cancer treatments. Strong odors, such as those in foods, are especially offending. Sometimes people are so sensitive to smell, they become easily nauseated.


Side effects of chemotherapy can lead to alterations in the senses of taste and smell. This is a common side effect of many chemotherapy medications and regimens used to treat many types of cancer.

As chemotherapy is processed throughout the body, it can produce a variety of odors that can come through the skin, urine, feces, or sweat.


Some side effects of chemotherapy and other cancer treatments are unavoidable. However, there are some steps you can take to help remain as comfortable as possible. 

If your sense of smell is sensitive, and possibly causing nausea, avoiding being around smells that you're sensitive to can be helpful. To manage the smells that come from food, the following can be helpful:

  • Try foods that can be eaten raw.
  • Don’t eat in rooms that are too warm.
  • Eat foods cool in temperature.
  • Avoid foods that have strong odors, such as fish or onions.

For those living with cancer who have ulcerated tumors that are possibly infected and causing a foul odor, talking to your cancer care team about ways to decrease the odor can be helpful. Sometimes medications can be given, such as antibiotics, to help decrease the odor.

Practicing proper skin hygiene can help you avoid infection, and subsequently, foul odor.


There can be odors from the VOCs associated with the development of cancer in the body that may be detected by specially trained dogs. Yet, this isn't the standard of care and more research needs to be done.These scents are generally undetectable by humans, though, and scientists are working on ways to measure these VOCs in urine and breath samples. 

The chemotherapy used to treat cancer may also cause a change in the smell of someone’s urine, feces, and sweat. 

A Word From Verywell

It may be strange to think that cancer can have a smell to it, but it’s true. Research is ongoing to determine the possibility of dogs being used to sniff out cancer while it's at an early stage.

If you’re living with cancer and have concerns about any odor changes in your body, be sure to talk to your cancer care team.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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