Baloxavir marboxil (BXM) is a novel anti-influenza agent that developed in Japan and inhibit the cap endonuclease specifically, and suggested the more clinical effectiveness in influenza. BXM reduces viral shedding more than do neuraminidase inhibitors (NAIs), and its clinical efficacy is equivalent to that of NAIs but is superior to that of NAIs in the case of type B influenza. BXM does not demonstrate any issues with safety, and treatment with BXM reduces the incidences of complicating sinusitis and bronchitis. Prophylactic administration of BXM inhibits intrafamilial transmission of influenza although low susceptible viruses with a PA/I38X substitution are isolated with a certain frequency following administration of BXM. Finally, In influenza treatment for patients aged 12−19 years and for adult outpatients, BXM can be used with the same recommendation level as oseltamivir.