Flomoxef is a cephamycin antibiotic with a difluoromethylthio-acetamido group at the 7-beta position of the cephem nucleus, commonly used for postoperative prophylaxis. Flomoxef has activity against epidermides, streptococci, propionibacteria, and both methicillin-resistant and -susceptible Staphylococcus aureus. Flomoxef exhibits a broad spectrum of antibacterial activity against G(+), G(-) and even anaerobes such as Staphylococcus sp., Escherichia coli, and Bacteroides sp., and it can be used singly to treat infection caused by aerobes and anaerobes (Mixed infection) effectively. Flomoxef belongs to the cephamycin, so it is very stable against β-lactamase as well as Extended Spectrum β-lactamase (ESBL), a novel resistance induced by Enterobacteriaceae. There is no Oxyimino group in the structure of Flomoxef, so it won’t derive ESBL and it is also effective for the treatment to ESBL infection. No disulfiram-like reaction and less incidence of vitamin K deficiency than that of Latamoxef. Marketed in Japan as FLUMARIN.