promote the production of gastric and pancreatic juice Tryptophan can be converted to an important neurotransmitter in human brain---- 5 - hydroxy tryptamine, which can act as norepinephrine and epinephrine and can improve the sleep duration. When the content of 5 - HT decreases in the brain of an animal, the abnormal behavior, insanity hallucinations and insomnia will occur. In addition, 5 - HT has a strong effect of vasoconstriction. It may exist in many tissues, including platelets and intestinal mucosa cells. The injured organism will stanch bleeding by the release of 5 - HT. Tryptophan is often used as anti-nausea agent, anticonvulsant, gastric secretion regulator, gastric mucosal protection agent and strong anti-coma agent.