fbpx Skip to Content

Can Dogs Smell Cancer In Humans?

Can Dogs Smell Cancer In Humans?
Can dogs smell cancer

It’s no secret that dogs have an incredible sense of smell. Thanks to their impressive abilities, we often see dogs in police investigations. Canines smell the traces of missing people, narcotics hidden in suitcases, or even the smell of decomposition that others tried to mask up. For a long time people also believed that dogs are able to smell diseases as well. But is that true? Can they really smell if there is something wrong with our bodies. And can dogs smell cancer?

The answer is yes! A dog’s sensitive nose can actually smell different infections, inflammations and cancerous cells in a person’s body or bodily fluids.

However, that doesn’t mean that you should panic the next time your dog starts to sniff some part of your body.

If you still need some convincing on how this is possible, continue reading this article.

Can dogs smell cancer?

Dogs can detect cancer odors in a person’s skin or bodily fluids such as sweat, urine, feces or blood. Cancer cells leave specific traces in our bodies that change our own personal smell. We as humans can’t detect that individual smell, but our dogs sure can. Even though their eyesight isn’t the best, our dogs would never confuse us with another person. That’s because they don’t know us by our appearance, but by our smell.

In cancer cells change the way our body smells to our dogs, they will start reacting differently.

The most common ways that dogs detect cancer is by the change in the smell of our skin, breath, feces, urine and sweat.

Trained dogs can pick up on these different odors and alert people to the changes in their bodies. We know these trained canines as medical detection dogs.

Well trained dogs can pick up on these smells even if their concentration is tremendously low. Their noses are sensitive enough to detect these smells even if the concentration is as low as parts per trillion.

What type of cancer can dogs smell?

Dogs detect different types of cancer. However, melanoma seems to be the most common one. Often dogs lick one specific spot on their owners skin that later gets diagnosed as melanoma.

Often, the dogs who detected the melanoma weren’t even trained. Trained dogs are able to detect a much wider range of cancers.

Dogs smell colorectal cancer in a person’s breath of feces. Dogs can smell this cancer even during the early stages. The same goes for lung cancer. Dogs smell it in a person’s breath. Ovarian and prostatic cancer change the smell of urine.

One study found that dogs trained to specifically detect breast cancer were also able to detect melanoma and lung cancer. This proves that a common odor can occur in different types of cancer.

Dogs smelling cancer licking it’s owners feet
Persistently sniffing, nibbling and licking one spot on your body is your dog’s way of letting you know that something isn’t right.

How do dogs act when they detect cancerous smells?

If a dog detects cancer he starts to persistently sniff, lick and nip on one specific spot on your body. This is especially common with melanoma. Melanoma causes lesions on the skin that your dog can smell even before they become visible to you.

This does not mean that you have to panic the next time your dog starts acting this way. Mostly, the easiest answer is the right one. Your dog might be picking up on different smells that have been building up on you during the day. The dinner you just prepared, the neighbor’s dog you petted, the Cheetos you ate while watching TV. Dogs love to smell you and get to know what you were up to during the day. But if your dog is focused on one specific spot on your body for days, just to be safe, schedule a chek-up.


Dogs have incredibly sensitive senses of smell. They can detect different odors and even the attendance of cancerous cells in our bodies. The most common cancer dogs detect is malignant melanoma, as it causes lesions in the skin that dogs smell (even through clothes).

When detecting cancer, dogs start to persistently sniff and nip at one specific spot on your body. If trained, dogs can detect many different types of cancer.

They pick up on the changes in our skin, sweat, urine and stool. Different cancers change the smell of different bodily fluids.

Medical detection dogs are still not a reliable way of diagnosing cancer. But researchers have hope that dogs will have a bigger role in cancer detection in the future.