Abstract

Nitric oxide (NO) is virtually present in every organ system, and can be detected in exhaled breath of healthy subjects in a concentration of 5 to 10 ppb (parts per billion). It plays a major role in the lung physiology and pathology. There are many studies about the value of measuring exhaled NO in diagnosing and monitoring the response to therapy in some diseases or using NO in the treatment. The aim of this review is to evaluate the source and the role of NO in the lungs.