Disease, believe it or not, has a smell. According to researchers, a machine with an 'electronic nose' can detect breast cancer - producing results that are as good as a mammogram.
Scientists now think that this may be applied to other diseases.
The BBC reported: "Throughout history, doctors have sniffed their patients' breath, urine, stool and other bodily fluids to help with diagnoses. A 2011 review article featured "smelling notes" of dozens of diseases. Yellow fever is said to smell like a butcher's shop, liver failure like raw fish, and typhoid like freshly baked brown bread."
The idea that sickness has an odour was explored in an experiment by a team led by Mats Olsson at the Karolinska Institute in Stockholm.
"He dressed eight healthy volunteers in tight, cotton T-shirts and injected one half of the group with a placebo and the other half with a chemical that gave them a mild flu-like reaction.
"A month later, the participants came back and were injected with the other solution - the one they had not received the first time. All the T-shirts were then collected and patches from the underarm area were cut out and placed in squeeze bottles. These were used to supply puffs of air to a panel of smelling volunteers."
For Olsson, one of the most interesting findings was that people seemed capable of sniffing out disease early on.
Here, according to Alphus D Wilson and Manuela Baietto's Advances in Electronic-Nose Technologies Developed for Biomedical Applications, published in Sensors, is what diseases smell like:
What to smell: skin Smell: butcher's shop
What to smell: skin Smell: freshly baked brown bread
What to smell: body Smell: stale beer
What to smell: sweat Smell: freshly plucked feathers
What to smell: mildly acetic (vinegar)
What to smell: breath Smell: raw fish
What to smell: breath Smell: nail polish remover
What to smell: urine Smell: ammonia (window cleaner)
What to smell: skin and sweat Smell: rotten apples