Dogs’ ability to detect disease through scent continues to be a focus of medical research. With an estimated sense of smell up to 100,000 times more sensitive than that of humans, dogs possess as many as 300 million scent receptors compared to the human count of six million. Their brains also dedicate significantly more capacity to processing smells.
This heightened olfactory ability has led researchers to explore how dogs can aid in diagnosing diseases. For example, changes in skin secretions in people with Parkinson’s disease produce a specific odor that trained dogs can identify, potentially serving as an early biomarker for the condition. Dogs are already used in some cases to recognize metabolic shifts before epileptic seizures and detect changes in blood sugar levels for people with diabetes. Additionally, they have shown accuracy in identifying certain cancers and COVID-19 infections.
These abilities are possible because humans constantly emit volatile organic compounds (VOCs) through sweat, breath, or urine. Each disease can produce a unique combination of VOCs that dogs are able to distinguish due to their acute sense of smell.
However, using dogs for medical diagnosis presents challenges. Training is intensive and time-consuming; it involves teaching the dog to recognize specific scents and then ensuring reliability through extended testing periods that may last months or longer. Dogs may also experience stress or nose fatigue from repeated exposure, which can reduce their sensitivity temporarily.
Despite these obstacles, interest in canine-assisted diagnostics is growing globally. Studies are underway examining whether dogs can identify breast cancer via sweat samples and expanding into detection of various viral and infectious diseases. There is also ongoing work combining dog research with chemical analysis techniques aimed at developing diagnostic instruments based on VOCs.
Research efforts extend beyond human medicine: scientists are investigating whether similar sniff tests could help diagnose aggressive cancers found in dogs themselves.
“Despite these limitations, a potential role for dogs in diagnostic medicine continues to expand,” according to UCLA Health Sciences Media Relations. “Proposed and ongoing studies are being done all over the world.”
For further questions about this topic or related health issues, readers may contact Ask the Doctors at UCLA Health Sciences Media Relations.
