Tecovirimat is primarily used as an antiviral medication to treat human smallpox disease caused by the variola virus. It works by inhibiting the viral envelope protein VP37, which is essential for the production of extracellular virus particles, thereby preventing the spread of the virus within the body. Although smallpox has been eradicated, tecovirimat is stockpiled as a precautionary measure in the event of a bioterrorism attack involving the virus. Additionally, it has shown efficacy against other orthopoxviruses, such as monkeypox and cowpox, making it a valuable therapeutic option during outbreaks of these rare infections. Its use is typically reserved for severe cases or for individuals at high risk of complications.