II avlod sefalosporinlar guruhidan, parenteral kiritish uchun mo'ljallangan sefamitsin antibiotik. Bakteritsid ta'siri bakterial transpeptidazalarni bloklash orqali mikroorganizmlarning hujayra devorining sintezining oxirgi bosqichlarini buzilishiga olib keladi. Aerob va anaerob bakteriyalarga nisbatan keng antimikrob ta'siri mavjud. Sefoksitin molekulyar tuzilishi uning bakterial β-laktamazalarga yuqori qarshiligini belgilaydi. Gram-musbat aeroblarga faol: Staphylococcus aureus, Staphylococcus epidermidis (penitsillinaza ishlab chiqaruvchi va ishlab chiqarmaydigan shtammlar), A guruhidagi beta-gemolitik streptokokklar (Streptococcus pyogenes), B guruhidagi beta-gemolitik streptokokklar (Streptococcus agalactiae), Streptococcus pneumoniae; gram-manfiy aeroblarga: Escherichia coli, Haemophilus influenzae, Eikenella corrodens (β-laktamaza ishlab chiqarmaydigan shtammlar), Klebsiella pneumoniae, Neisseria gonorrhoeae (penitsillinaza ishlab chiqaruvchi va ishlab chiqarmaydigan shtammlar), Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia spp. (jumladan Providencia rettgeri), Salmonella spp., Shigella spp.; anaeroblarga: Actinomyces spp., Clostridium spp. (Clostridium difficile dan tashqari), Peptococcus niger, Peptostreptococcus spp., mikroaerofil streptokokklar, Bacteroides spp. (jumladan Bacteroides distasonis, Bacteroides fragilis, Bacteroides ovatus, Bacteroides thetaiotaomicron), Prevotella bivia. Sefoksitin metitsillin-chidamli Staphylococcus spp., Enterococcus spp., Listeria monocytogenes, Enterobacter cloacae, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Mycobacterium spp., Rickettsia spp., Chlamydia spp., Mycoplasma spp., Ureaplasma spp. ga faol emas.