In some cases, researchers have even trained household pets to detect cancer
or predict epileptic seizures
But what if we could fine tune that sense and put it into a microchip, allowing us to create a breathalyzer for diseases?
For Dr. Andrew Koehl, the inventor of the microchip spectrometer technology at the heart of this "digital nose", the technology that will allow us to do just that is already here.
"We can detect down to parts per billion levels," Koehl says. "To give you an analogy that's equivalent to one drop in an Olympic size swimming pool."
The sensor, which is no bigger than a dime, works by creating a spectrum of what chemicals are in the air. It then identifies each chemical's unique make-up. If the sensor is set and calibrated to a certain level, it will trigger an alarm.
Work continues to shrink it even further in a bid to enter the healthcare market. Within several years, the company hopes to develop it as a diagnostic tool.
"What's amazing is that there really are compounds on your breath that indicate illness, that's been shown through a number of studies and we can detect those," he said.
"There have already been a number of research papers published suggesting we can detect cancer, detect tuberculosis, detect asthma."
Initially, the technology had been developed for defense purposes.
He said the threat posed by the events of September 11 had got him thinking about the security applications of this type of sensor.
"Originally it was aimed at detecting things like explosives, toxic chemicals and other threats that might occur," Dr Koehl told CNN.
Developed at a research lab at the University of Cambridge in the UK and now in commercial production at a company called Owlstone with close links to the university, Dr Koehl says the sensor is already in use by oil industry giants like BP and Shell and in the food industry by Coca Cola and Nestle.
Eventually the sensor could become a part of many everyday appliances, alerting consumers to which foods are going bad in the fridge or even the optimum moment to take the roast out of the oven.
You could even, one day, have a digital nose that you could carry in your hip pocket.
"More recently we've been looking at consumer spaces so we're talking to a number of manufacturers of mobile phones and mobile phone components," he said. "We want to develop a module small enough to put into mobile devices like phones."