Lysine is an indispensable protein for the organism and can only be obtained through exogenous intake. It is recommended to take lysine on an empty stomach to facilitate drug absorption. Lysine is one of the essential amino acids and has the function of promoting the metabolism of brain cells. It is often used as a nutritional supplement for children or patients with cranio-cerebral injury or malnutrition, and has a certain effect of promoting intellectual development. However, this drug is an acidic drug and should be taken after meals for patients with serious gastrointestinal diseases, such as gastroduodenal ulcer and gastric bleeding, to avoid gastrointestinal discomfort symptoms. Add more meat, eggs, milk, as well as fish, shrimp and sea shells to the usual diet to facilitate the intake of lysine.