Colitis anal pain may be caused by inflammatory reaction, mucosal injury, constipation and other reasons. 1. Inflammatory response: if colitis is caused by bacterial, fungal, viral infections, diarrhea, abdominal pain, mucus stools and other symptoms, the anal mucosa is repeatedly stimulated by inflammation and lead to anal pain. 2. Mucosal damage: if caused by parasites and protozoa, increased defecation will damage the anal mucosa, which will also lead to anal pain. 3. Constipation: some patients with colitis will be constipated, or even not defecate for several days. Excessive force during defecation can lead to cracking of the skin at the anal verge, resulting in anal pain. Colitis patients with anal pain should be recommended to seek timely medical care, under the guidance of a professional physician to clarify the cause of the disease, and give early treatment.