Baloxavir marboxil is an antiviral drug used to treat influenza. More specifically, it is a first-in-class cap-dependent endonuclease inhibitor that works to block influenza virus proliferation. It is a prodrug of [baloxavir] with an improved absorption profile than its active metabolite due to the addition of a phenolic hydroxyl group to its structure. Baloxavir marboxil was first globally approved in Japan in February 2018, followed by the US approval in October, 2018. It was also approved by the European Commission on January 7, 2021.