Fractional exhaled nitric oxide (FeNO) is a noninvasive biomarker that reflects type 2 airway inflammation. Elevated FeNO levels are a result of increased nitric oxide production by airway epithelial cells. While various factors can influence FeNO levels, its measurement offers valuable insights into asthma management. This infographic explores how FeNO can support the diagnosis of asthma, provide prognostic information regarding lung function decline and exacerbation risk, and predict patient response to some therapies.