Hard nodules at the anal opening may be anal canal cancer, anal warts, hemorrhoids and other diseases. 1. Anal canal cancer: anal canal cancer usually refers to malignant tumors occurring below the dentate line to the opening part of the anus, which may be related to environmental factors as well as hereditary factors of the patient, and the patient may have symptoms such as anal mass, blood in stool, itching, pain and so on. 2. Anal warts: anal warts are usually the growths caused by infection with human papilloma virus, usually due to the patient’s unclean sex life, personal hygiene, long-term friction and other reasons, the patient may appear perianal local hard growths, itching, pressure, slight tingling and other symptoms. 3. Hemorrhoids: hemorrhoids are generally hypertrophic downward displacement of the anal cushion resulting in localized subcutaneous vascular enlargement of the anus, which may be related to the patient’s dietary habits, lifestyle and other factors, the patient may experience perianal swelling, blood in the stool, pain and other symptoms. There are hard nodules in the anus, once found, it is recommended that the patient timely diagnosis and examination to determine the cause of the disease, as soon as possible standardized treatment, to avoid delaying the aggravation of the condition.