Used in cancer treatment, particularly for colorectal, breast, and gastrointestinal cancers. Acts as an antimetabolite that interferes with DNA and RNA synthesis in rapidly dividing tumor cells. Often employed in chemotherapy regimens either alone or in combination with other agents. Its fluorine substitution enhances metabolic stability and improves tumor selectivity. Also investigated for use in topical formulations for skin cancers due to favorable tissue penetration and localized effect.