Used in cancer treatment, particularly for solid tumors such as colorectal and breast cancer. It acts as a prodrug that is converted in the body to 5-fluorouracil (5-FU), a potent antimetabolite that interferes with DNA and RNA synthesis in rapidly dividing cancer cells. Its selective activation in tumor tissues helps reduce systemic toxicity compared to direct 5-FU administration. Also investigated for use in combination therapies to enhance treatment efficacy and overcome drug resistance.