What is the concentration of hydrochloric acid in gastric juice?

Gastric juice is the digestive fluid produced in the stomach. It contains hydrochloric acid (HCl), pepsin, and mucus. Typical concentrations of hydrochloric acid in gastric juice range from 0.5% to 1%. Hydrochloric acid creates the highly acidic environment in the stomach that is necessary for activating pepsin and beginning the process of protein digestion. Hydrochloric acid also kills germs that enter the stomach.