From diabetes smelling like nail polish remover to liver failure smelling of raw fish, doctors say diseases could eventually be diagnosed just using smell.
They say that the breath of people with diabetes has been reported to smell of nail varnish remover, while that of those with liver disease can smell of raw fish.
And even if the smell is too subtle to be detected by humans, it could soon be picked up by "electronic noses".
The researchers, who published their findings in the journal Sensors, also explain that a bladder infection can make the urine smell of ammonia and rubella can make the sweat smell of freshly plucked feathers.
Schizophrenia can make the sweat smell of vinegar and typhoid makes the skin smell like freshly baked bread, the BBC reports.
Finally, yellow fever can make the skin smell like a butcher's shop and scrofula - a lymph node infection - can make a patient smell of stale beer.
Within the last week researchers have also discovered that machines can "sniff out" breast cancer and that they are just as effective as a mammogram.
One patient even claims that she was is able to detect the smell of cancer herself.
Joanie wrote on an online forum that when her husband was suffering from prostate cancer, and when she had lung cancer, she could smell decay.
She says that the smell disappeared when the cancer was treated.
Seemingly, she is not alone - Dr George Preti at the Monell Chemical Senses Center in Philadelphia says he has heard numerous reports of patients noticing an unpleasant smell when around someone with cancer.
Dr Preti says he hopes this finding could lead to new ways to diagnose cancer earlier.
He is particularly interested in ovarian cancer which is often not diagnosed until it is at an advanced stage.
Dr Preti says that the body produces chemicals as a result of normal metabolism but that cancerous cells metabolise differently meaning they emit different chemicals and cause a different smell.
This is usually too subtle for humans to detect but dogs have been trained to diagnose cancer as well as diabetes.
As a result, Dr Preti is now collaborating with the Penn Vet Working Dog Center in a bid to teach dogs to sniff out ovarian cancer.
Dr Preti says the four dogs receiving the training are able to detect the disease 90 per cent of the time.
He hopes the dogs will help him to identify a unique "odour signature" for the cancer.
This would then allow him to programme an "electronic nose" to detect the disease.
Dr Preti told the BBC: "You can have the power of a dog's nose on this small chip the size of your fingernail. It's this device, rather than the dogs, that might end up on hospital wards."
Dogs, however, are not the only creatures that are able to detect cancer.
Scientists believe that fruit flies also have this ability.
Researchers at the University of Konstanz, in Germany, found the smell of cancer cells can cause a specific pattern of activity in the flies' antennae.
The researchers hope they will eventually be able to grow their own antennae which they could use to detect disease.
Another device is closer to hitting the market.
Tests on an "electronic nose" called BreathLink revealed it can detect breast cancer in a patient's breath.
The device can give results within 10 minutes and could prevent patients from having to be exposed to X-rays.
It could save millions of women from painful mammograms.
It is being tested at the University of Maastricht Medical Centre in The Netherlands and could be available to doctors within just two years.
At about the same time, another company, called Owlstone, is hoping to make available a device that can sniff out bowel cancer.
Just a few weeks ago, researchers at the Karolinska Institute, in Sweden, discovered that humans can smell if someone's immune system is highly active.
They discovered that people can smell that the immune system has gone into overdrive within just a few hours of exposure to bacteria.
The researchers injected a group of volunteers with a toxin that induced an immune response.
They then asked them to wear tight t-shirts and discovered that when another group of people smelt these t-shirts, they thought the sweat had a more unpleasant smell than that from people whose immune systems were not in overdrive.
What do diseases smell like?
Diabetes can make the breath smell of nail varnish remover.
Liver failure can make the breath smell of raw fish.
A bladder infection can cause the patient's urine to smell of ammonia.
Rubella can make the sweat smell of freshly plucked feathers.
Schizophrenia can make the sweat smell of vinegar.
Typhoid makes the skin smell like freshly baked bread.
Yellow fever can make the skin smell like a butcher's shop.
Scrofula - a lymph node infection - can make a patient smell of stale beer.
- DAILY MAIL