Gastric juice has pepsin, lipase, and rennin in it. Pepsin is secreted as pepsinogen in an inert form which is activated by hydrochloric acid. Pepsin metabolises proteins into peptones. Lipase helps to break the presences of fat in our body into fatty acids. Rennin is a proteolytic enzyme which is useful in milk coagulation.
Succus entericus also called intestinal juice is a fluid secreted in the small intestine in small quantities. Succus entericus is the alkaline secretion produced by glands in the duodenum wall, which consists of water, mucoproteins, and carbonate hydrogen ions. This intestinal juice is formed by the secretions of the mucosal brush boundary cells along with the secretions of goblet cells. It helps counteract the highly acidic and proteolytic chyme entering from the stomach into the small intestine, and thus protects the duodenum against damage.