In mild cases of proctitis, only the mucosa is inflamed, while in severe cases, the inflammation involves the submucosal layer, muscular layer, and even the tissues around the rectum; sometimes only part of the rectal mucosa is affected, sometimes the entire rectal mucosa is inflamed, and part of the mucosa of the colon may also be inflamed. Proctitis is common in people with weak constitutions and low resistance, heart, lung, liver, gastrointestinal diseases, respiratory infections, infectious diseases, constipation, diarrhea, hemorrhoids, anorectal prolapse, anal fistula, polyposis, anorectal stenosis, rectal tumors, rectal injuries, foreign bodies, etc., which can all cause rectal inflammation. Severe cases require immediate surgical treatment in the hospital. The most common cause is foreign body injury in the rectum. Undigested bone fragments, wood chips, or other foreign bodies with sharp corners can directly damage the rectal mucosa and cause proctitis. In addition, hard stool lumps during severe constipation can cause proctitis.