&NA;Squamous‐cell carcinoma of the anus is an uncommon but treatable gastrointestinal malignancy. Radiation, in addition to chemotherapy, is widely accepted as the standard of care for treatment in most patients. However, significant anal complications, such as stricture, fistula, and ulceration, may result from radiation therapy. Some medical therapies have been used for radiation proctopathy, but treatments for radiation‐induced anal injury other than surgical diversion are unknown. Vitamin A has been shown in laboratory studies to facilitate wound healing and prevent radiation‐induced gastrointestinal damage. However, it has not been used clinically in patients with radiation enteritis, proctopathy, or anal ulceration. We report a case of a patient with human immunodeficiency virus infection who developed a symptomatic anal ulcer after receiving high‐dose radiotherapy for anal squamous‐cell carcinoma. We prescribed 8,000 IU of oral vitamin A twice daily and within seven weeks his anorectal symptoms and anal ulcer completely resolved. Vitamin A seems to be very effective in the treatment of radiation‐induced anorectal damage, with little toxicity and expense.