In ancient times, physicians were aware of the relationship between the odour of a subjects’ breath and possible diseases associated with it. They realized it could provide insight into physiological and pathophysiological processes in the body.

It is common knowledge that the sweet acetonic smell of breath might indicate uncontrolled diabetes whereas a fishy reek of breath relates to liver disease and a urine-like smell is associated with kidney failure. Apparently, there is something present in breath that might enable diagnosing certain diseases. Due to the great potential of applications in clinical diagnostics and its non-invasive nature, exhaled air analysis has become of increased interest in recent years.

Exhaled air breath analysis (breathomics) can be applied as an analytical and monitoring tool. In the analytical perspective, Volatile Organic Compounds (VOCs) may be used as biomarkers of oxidative stress, inflammation or carcinogenesis.

As monitoring tool, breathomics can be applied to elucidate the heterogeneity observed in diseases, to study the pathogen responsible for an infection and to monitor treatment efficacy.