Anal sinusitis does not usually cause flat stools. Anal sinusitis, also known as anal cryptitis, is an inflammatory lesion of the anal crypts in the dentate line of the anus. The cause is the special anatomical shape of the anal sinuses, the sinuses are easy to accumulate feces or blocked by secretions, resulting in infection and inflammation. Common clinical manifestations are anal pain during defecation, accompanied by urgency and heaviness (discomfort in the lower abdomen, wanting to defecate very much, and a feeling of incomplete defecation after defecation), a feeling of falling in the anus with the urge to defecate, but go to the toilet but can not solve or solve very little feces, and feces can be with a small amount of mucus and blood. The feces may contain a small amount of mucus and blood. Therefore, there is no phenomenon of flattening of the stool. Performing anal finger examination, there may be sphincter tension, anal sinus and papilla hardness and tenderness, anoscopy can be seen in the anal sinus, anal papilla congestion and redness and swelling. It is recommended that if the phenomenon of flat stool, go to the hospital in time to do the relevant examination, after clarifying the cause of the disease, do the corresponding treatment and treatment, to avoid delaying the condition.