Efudex (Fluorouracil, Carac) is prescribed for the treatment of actinic or solar keratoses (small red horny growths or flesh-colored wartlike growths caused by overexposure to ultraviolet radiation or the sun). Such growths may develop into skin cancer. When conventional methods are impractical—as when the affected sites are hard to get at—the 5 percent strength of Efudex is useful in the treatment of superficial basal cell carcinomas, or slow-growing malignant tumors of the face usually found at the edge of the nostrils, eyelids, or lips.