Colitis is relatively common in clinical settings, especially in the gastroenterology outpatient department, and it generally occurs in middle-aged and elderly patients. The disease typically begins with abdominal pain, diarrhea, or abnormal stools. The abdominal pain is characterized by episodic pain in the lower left or right abdomen, without persistent episodes and generally does not occur after the patient falls asleep at night. The diet is usually not related. Diarrhea manifests as watery stools or stools with a soft texture, without bloody stools. Abnormal stools are characterized by constipation, for instance, if the patient has not had a bowel movement for several days, with dry, sheep-dung-like stools that are difficult to expel. Typically, after a thorough colonoscopy, no colon tumors or polyps are found, but signs of congested and edematous colonic mucosa suggest a diagnosis of colitis. Generally, the condition isn't severe, and treatment primarily involves symptomatic management.