The causes of colitis are: 1) environmental and dietary differences, whether or not smoking, good or bad hygiene in the place of residence, different methods of living, taking birth control pills, appendectomy, etc., may be environmental factors; 2) genetic, the incidence of first-degree relatives of patients with colitis is significantly higher than that of the general population, while the incidence of spouses does not increase; 3) infection, there are a variety of microorganisms involved in the process of disease progression. A history of intestinal infections and dysbiosis of normal intestinal flora before the onset of the disease is also a causative factor; 4, immunity, sustained immune response and excessive activation of TH1 cells, releasing a large number of immune mediators causing damage to the intestinal mucosa, resulting in ulcers that do not heal over time, inflammatory hyperplasia and other symptoms; 5, mental stress, anxiety, and food allergies can also increase the risk of colitis.