The hardness and swelling in the anus may be caused by internal hemorrhoids, anal fistula, rectal cancer or perianal abscess. 1. internal hemorrhoids: internal hemorrhoids is due to poor dietary habits or habits and other factors, resulting in the anal canal dentate line above the end of the rectum submucosal vascular plexus expansion as well as varicose to form a mass, essentially belonging to the varicose veins vascular mass, so that the patient appeared to the anus with a hard lump in the swelling of the feeling. 2. Anal fistula: anal fistula is a perirectal abscess broken or incision and drainage of residual lesions, poor diet and lifestyle habits can induce the disease, anal fistula sinus tract may be accompanied by hard lumps, resulting in the patient feels swollen in the anus. 3. Rectal cancer: Rectal cancer is a malignant tumor originating from the rectosigmoid junction to the dentate line, which may be related to environment, diet, heredity and living habits, etc. In the early stage, there is no conscious symptom, and with the development of the disease, the patient will have the feeling of hardness and swelling in the anus. 4. Perianal abscess: Perianal abscess refers to the acute purulent infection of the soft tissues around the anal canal and rectum or the surrounding interstitial space, purulent material oozing out of the collection will form an abscess, which mainly manifests itself as persistent perianal swelling and pain, and with the development of the disease, patients may appear to have a hard lump in the anus and swelling sensation. There are many factors that can lead to swelling and hard lumps in the anus, and it is recommended to go to the hospital for examination and diagnosis in time to determine the cause of the disease and then carry out targeted treatment, so as to avoid any misunderstanding of the condition.