After relieving the stool anal side buttocks swollen, may be hemorrhoids, perianal abscess, tumor and other reasons. 1. hemorrhoids: various reasons for stimulation of the anal venous plexus and arteriovenous anastomosis branch pathological changes, (or) subcutaneous veins pathologically dilated, connective tissue hyperplasia caused by, may lead to relieve the stool, the anal side of the buttocks swollen. 2. Perianal abscess: refers to the anal canal and rectum around the interstices of purulent infection, purulent secretions oozing and accumulating to form an abscess, can also lead to relieve the bowel movement, anus side buttocks swollen phenomenon. 3. Tumor: rectum or anal canal and other local benign tumors or malignant tumors, lesions can also cause the feeling of swelling of the anus side of the buttocks after finishing the stool. Swollen buttocks on one side of the anus, there may be other causes, it is recommended that the patient go to the hospital for examination in a timely manner, to clarify the cause of the disease, and follow the doctor’s instructions to give treatment as soon as possible to avoid aggravation of the condition.