Fluorouracil is a medication in the antimetabolite class of prescription drugs. Fluorouracil is primarily used in the treatment of many different types of cancer and pre-cancerous growths. The drug can be administered either as a topical cream in the event of skin cancer, pre-cancerous growths of the skin, or, in the event of other forms of cancer, as an intravenous injection. The function of the drug is to prevent cancerous cell growth. Fluorouracil is a drug found in the anti-metabolites drug class. It is one of the most recognized drug used in treating pre-cancerous growths and cancer, especially on the skin. It is also prescribed by medical practitioners to treat breast, anal, esophageal, pancreatic, and stomach cancers. Fluorouracil works through the inhibition of the thymidylate synthase. As such, Fluorouracil blocks the further growth of abnormal cells that results in cancer. It is available in different forms, but the most commonly recommended is an ointment applied on the skin. Follow the prescription details by the medical practitioner to reduce risks of severe side effects.