The left lower abdomen is the location of the descending colon and the sigmoid colon, because the sigmoid colon is sinuous, colon disease is often high in the sigmoid colon part, not only the high incidence of colitis, but also the high incidence of colon polyps location. If distension occurs, consider chronic colitis or acute enteritis. Chronic colitis may be caused by immune factors or long-term inflammatory stimulation, while acute colitis considers gastrointestinal spasm caused by dietary unhygienic or external environmental stimulation. The anal drop is considered to be proctitis, which is mostly caused by inflammatory stimulation, foreign body stimulation or anal disease stimulation. Proctitis accumulates the end of the anus, rectum and sigmoid colon, and still needs to exclude urological diseases as well as gynecological diseases.