In general, the early symptoms of colitis are: 1. abdominal pain: patients mainly show mild or moderate abdominal pain around the umbilicus or the whole abdomen, which can also involve the whole abdomen. 2. blood in the stool: there is a small amount of blood in the stool, which can be shown in black stool or tarry stool. If the bleeding is large, there can be fresh blood in the stool. 3. Intestinal stricture: Early colitis does not have clinical manifestations of intestinal stricture. If the condition is repeatedly attacked and not treated in time, it can cause intestinal stenosis and eventually lead to intestinal obstruction which is intestinal perforation.4. Intestinal perforation: It is a more dangerous symptom, and after the attack it can manifest as sudden and severe abdominal pain, which then spreads to the whole body.5. Toxic colitis: It mainly manifests as patients’ chills, fever, and high abdominal distension.6. Colon cancer.7. Diarrhea: There are light and heavy, and light diarrhea may be 2-3 times a day, mainly with thin watery stools. Heavy stools mixed with pus or pus and blood.8. Constipation: constipated patients have difficulty in defecation, difficult to relieve and dry.9. Systemic symptoms: patients mostly have wasting, weakness, insomnia, and in severe cases, chills and fever, anemia and other accompanying symptoms.