Constipation after anal fissure surgery can be caused by pain in the operation area, poor diet after operation and other factors. 1. Pain in the operation area: after anal fissure surgery, pain symptoms can appear at the anal opening and the surgical incision. When changing medicine for the wound, the local area may also show severe pain, so it is easy to have a sense of fear of defecation, which may lead to poor defecation and cause constipation. 2. Poor dietary habits after surgery: after anal fissure surgery, the patient still fails to develop good dietary habits in time, after eating spicy and stimulating foods, greasy foods, etc., which may lead to dry stools and difficult defecation, and constipation is easy to occur. 3. Constipation: People with anal fissure usually have the symptom of habitual constipation. If the constipation situation is not significantly improved after the surgery, coupled with the fear of defecation, the constipation symptom will be aggravated. If you are constipated after anal fissure surgery, you should consult a doctor in time, pay attention to developing good dietary habits and adjusting your mindset, which will help you to relieve the discomfort as soon as possible.