Can’t hold stool but not diarrhea may be related to the physiological reasons of the elderly anal sphincter ability to decline, but also may be related to anal surgery, intestinal inflammation, neurological diseases and other pathological reasons, as follows. 1. Physiological reasons: the control ability of the anal sphincter is weakened in the elderly due to the relaxation of the anal muscles, which will lead to anal incontinence and the situation of not being able to hold in the stool. 2. Pathological reasons (1) Anal surgery: if you have had anorectal surgery before which causes damage to the anal sphincter, you will have fecal incontinence after the surgery. (2) Congenital causes: If there is congenital anal atresia or congenital anal dysplasia, the anal sphincter function is weak, and fecal incontinence will also occur. (3) Neurological diseases: if there are spinal cord injuries, cerebrovascular accidents, etc., because the nerves innervating the anal sphincter are damaged, fecal incontinence can also occur. There are more reasons for incontinence of bowel movement, so it is recommended to consult a doctor for a clear diagnosis in time to avoid delaying the condition.