Senna leaf is not recommended for young people. It is a common laxative, and it is mainly used for constipation due to heat accumulation and abdominal distension. In hospitals, it is often used as a bowel cleanser before intestinal examination, or to relieve constipation for some patients with acute constipation. Many people think that senna is a natural medicine, which is safe and reliable. In addition, it is cheap and convenient to take. Many people buy senna to treat constipation or lose weight. However, in recent years, the adverse reactions related to senna have appeared frequently, and the common ones are: toxic and side effects of gastrointestinal system: sennoside contained in senna can inhibit the absorption of water in the large intestine, make the intestinal contents increase sharply, and at the same time increase the tension of the large intestine, causing abdominal pain, nausea, vomiting, etc. In severe cases, it can induce upper gastrointestinal bleeding, manifested as epigastric pain, vomiting coffee-like liquid or tarry stool. Therefore, people with gastric ulcer or a history of gastrointestinal bleeding cannot use senna.