Pepsin is a component of gastric juice and is associated with protein digestion. It is an endopeptidase that catalyzes the degradation of proteins into peptides and amino acids for small intestinal absorption. Pepsin is released as a zymogen (pepsinogen) by the chief cells of the gastric lining. It gets activated by the acidic environment created by the hydrochloric acid (HCl) of gastric juice. Pepsin is active at pH 1.5 to 2, in the stomach. It is involved in the conversion of food bolus into chyme. It is associated with laryngopharyngeal reflux (LPR) indicated by chronic cough, mild dysphagia, hoarseness, and non-productive throat clearing.