Edoxudine is a synthetic thymidine analog used as an antiviral agent, primarily in topical formulations for the treatment of herpes simplex virus (HSV) infections, especially herpetic keratitis (ocular herpes). It functions by incorporating into the viral DNA during replication, acting as a chain terminator that inhibits viral proliferation. While it has been investigated for other HSV-related conditions, such as cutaneous infections including herpes labialis, its use is limited and not first-line therapy. As a high-purity chemical reagent (≥99%), it is also employed in pharmaceutical research and development for antiviral studies.