6 Human Diseases Dogs Can Detect by Scent

Dogs have an extraordinary sense of smell—far superior to ours—which offer more than just a way to sniff out treats. It turns out, our furry friends possess the incredible ability to detect a range of diseases in humans, simply by scent. 

Their noses might hold the key to early detection and potentially life-saving interventions. And what’s even more astonishing is that the list of diseases they can sniff out is only growing.

1. Parkinson’s

6 Human Diseases Dogs Can Detect by Scent - parkinsons dp185676854
Image Credit: daisy-daisy/Deposit Photos

A study explored the potential of sniffer dogs to differentiate between Parkinson’s disease (PD) patients who were on medication, those who were not, and individuals without the disease.

The results were impressive, with the dogs demonstrating a sensitivity of 91% for medicated PD patients and 89% for unmedicated patients.(ref)

Building on this promising research, a clinical trial is currently underway to further investigate the ability of dogs to distinguish between individuals with PD and those without.(ref) The ultimate goal is to utilize these canine abilities for early detection of Parkinson’s disease, potentially leading to earlier interventions and improved outcomes for patients.

2. Cancer

6 Human Diseases Dogs Can Detect by Scent - cancer patient ss295942139
Image Credit: ESB Professional/Shutterstock

Studies have proven that trained dogs can accurately sniff out various forms of cancer, such as melanoma, bowel cancer, lung cancer, ovarian cancer, prostate cancer, and breast cancer. In fact, a 2021 study showed a remarkable 100% accuracy rate in a trained dog detecting breast cancer from urine samples.(ref)

Interestingly, some dogs display this uncanny ability without any formal training. In one instance, a rescue dog persistently licked a seemingly harmless spot behind her owner’s ear, leading to a diagnosis of malignant melanoma.(ref) 

3. Diabetes

6 Human Diseases Dogs Can Detect by Scent - diabetes ss2300488795
Image Credit: JLco Julia Amaral/Shutterstock

Diabetic alert dogs (DADs) are specially trained service dogs that can detect fluctuations in blood sugar levels, alerting their diabetic owners to both high and low glucose levels, which can be life-threatening if not addressed promptly.

Research suggests that dogs have the extraordinary ability to detect a volatile organic compound (VOC) called isoprene, which is released when blood sugar levels drop. This VOC is undetectable to humans, highlighting the unique olfactory capabilities of dogs. A 2016 study from the UK provided evidence supporting this phenomenon.(ref)

Furthermore, a 2019 study investigated the reliability of dogs in detecting abnormal blood sugar levels. While individual dog performance varied, the study found that, on average, 81% of alerts from the dogs occurred when blood sugar levels were outside the normal range, either too high or too low.(ref)

4. Migraines

6 Human Diseases Dogs Can Detect by Scent - man with headache ss292792988
Image Credit: pathdoc/Shutterstock.

While the idea of dogs detecting migraines is often anecdotal, a study involving 1,029 adults with migraines found that over half (53.7%) reported a noticeable change in their dog’s behavior before or during this initial phase.(ref) This change in behavior typically occurred within two hours prior to the onset of migraine symptoms.

The observed behaviors varied but often included the dog staring intently at their owner, refusing to leave their side, physically comforting them by sitting or lying on them, or even guiding them towards a place of rest like a bed or couch. This suggests that dogs may possess an intuitive ability to sense the subtle physiological changes that occur before a migraine, offering potential for early warning and intervention.

5. Narcolepsy

6 Human Diseases Dogs Can Detect by Scent - men in hospital ss1318617428
Image Credit: Rocketclips, Inc./Shutterstock

Narcolepsy, a chronic neurological condition, disrupts the brain’s natural sleep-wake cycle, causing individuals to experience sudden and uncontrollable sleep attacks. 

Intriguingly, a 2013 study revealed the potential of trained dogs to identify individuals with narcolepsy. In this research, the dogs successfully detected 11 out of 12 narcoleptic participants, suggesting that individuals with this condition may emit a unique odor that dogs can perceive.(ref) This finding opens up the possibility of using trained dogs as a non-invasive diagnostic tool or even as an early warning system for narcoleptic episodes.

6. COVID-19

6 Human Diseases Dogs Can Detect by Scent - woman in hospital ss1668007552
Image Credit: Ground Picture/Shutterstock.

A recently published review of existing peer-reviewed studies has concluded that trained scent detection dogs can be equally effective, if not more so, than the current COVID-19 tests we rely on, including both PCR tests and rapid antigen tests (RATs).(ref)

Furthermore, the review highlights the remarkable ability of dogs to accurately identify the SARS-CoV-2 virus even in the presence of other respiratory viruses, such as those causing the common cold or flu. This means that their detection capabilities are not hindered by the presence of other illnesses, making them a potentially valuable resource in identifying COVID-19 cases.

As research continues to uncover the full extent of their capabilities, we can only imagine the future role of dogs as our four-legged partners in health. The bond between humans and dogs has never been more profound or more promising.

davin
Website | + posts

Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.