Stool thinning defecation as far as possible is physiological, may also be pathological factors such as perianal abscess, colitis, intestinal tumors and other causes. 1. Physiological factors: such as the consumption of greasy, spicy and stimulating food, can produce stimulation of the intestinal tract, accelerate gastrointestinal peristalsis appeared in the symptoms of stool thinning and exhaustion. 2. Pathological factors (1) perianal abscess: perianal lumps, can cause pain in the anus, swelling, the lump becomes bigger can cause stool thinning, and anal swelling can cause the symptoms of incomplete evacuation. (2) Colitis: Inflammatory stimulation can cause abdominal pain, thinning of stools and other symptoms, diarrhea can cause incomplete evacuation of stools, which can be related to mental and psychological factors. (3) Intestinal tumor: Tumor cells invade the colon, rectum and even anus, which stimulate the local area and cause thinning of stool and incomplete defecation. If the symptoms of incomplete bowel movement occur, it is recommended to go to the hospital in time to find out the cause and then treat it actively so as not to delay the condition.