Used primarily in the treatment of viral infections, especially ocular herpes simplex virus (HSV) infections. It functions as an antiviral agent by inhibiting viral DNA synthesis. Trifluorothymidine is commonly formulated as an ophthalmic solution or ointment for topical application to the eye. It is effective in managing acute and recurrent epithelial keratitis caused by HSV. Due to its mechanism of action, it may also have applications in cancer research, where it can interfere with DNA replication in rapidly dividing cells.