Severe colitis has no so-called characteristics. Severe colitis can be characterized by bloody stools, pus and blood stools, severe diarrhea, and shock. Severe colitis can have obvious damage to the intestinal mucosa, accompanied by blood circulation disorders, blood volume insufficiency, and involvement of other organs, which can be manifested as bloody stools, pus-blooded stools, severe diarrhea, and a significant increase in the number of stools, or shock manifestations such as wet and cold fingertips, cyanosis, decreased urine output, rapid heartbeat, and low blood pressure, and can also be manifested by rapid respiration and respiratory distress. There is no such thing as a characteristic of severe colitis; each patient has his or her own characteristics. Patients with severe colitis or with the above mentioned manifestations should go to the hospital in time and be given rehydration and antibiotic treatment by the doctor to correct electrolyte and acid-base balance disorders. Therefore, patients with severe colitis must pay great attention to it, otherwise it may be life-threatening.