The chemical composition of human breath holds a wealth of information regarding health. Although the clinical measurement of chemicals in breath is currently used in the diagnosis and treatment of heartburn, due to H. pylori infection, and g.i. problems, due to malabsorption, further application of the technique has been hindered by a lack of adequate analytical methods. This work presents a review of current applications of breath analysis. Following the review, a discussion of the genetic disorder cystic fibrosis (CF) is given, which includes a description of the biological origins of CF as well as the potential of breath analysis in its treatment. This work then outlines several studies carried out at the University of California, Irvine, under the supervision of Dr. Donald Blake, Dr. Dan Cooper, and Nobel Laureate Dr. F. Sherwood Rowland. These studies were aimed at characterizing the chemical composition of breath using a state-of-the- art form of chromatography. An important result of these studies was the discovery of carbonyl sulfide as a promising trace biomarker of pulmonary function in the breath of individuals with CF.