Cephalexin-d5 is deuterium labeled Cephalexin. Cephalexin (Cefalexin; Cephacillin) is a potent, orally active and the first-generation?cephalosporin antibiotic. Cephalexin kills?gram-positive?and some?gram-negative bacteria?by disrupting the growth of the bacterial cell wall. Cephalexin monohydrate is used for the research of?pneumonia,?strep throat, and bacterial endocarditis, et al[1].