Hemorrhoids 15 days after surgery serious edema like external hemorrhoids, there are several main reasons, such as surgical damage caused by venous, lymphatic reflux obstacles, anesthesia drug injection and squatting for a long time and so on. 1. surgical trauma: because hemorrhoid surgery is anal surgery, itself is not aseptic surgery, so the postoperative trauma is large, damage to the anus at the venous blood vessels, lymphatic vessels, and so on, which causes venous, lymphatic reflux obstacles, local edema, circulatory reconstruction can be eliminated after the swelling. 2. local anesthesia drugs: if the surgical process to take local anesthesia, if the injection of local anesthesia drugs too much can cause edema, in addition to postoperative trauma using long-acting local anesthesia drugs too much, can lead to traumatic edema, which in turn cause edema of the skin, shaped like external hemorrhoids. 3. long squatting: after surgery, if the patient has constipation, go to the toilet stool squatting time is too long, but also easy to cause the anal wound edema. Mild edema can be self-swelling, and severe edema, can not be self-subdued, it is recommended to go to the hospital, by a professional physician to deal with.