Moxalactam is a β-lactam antibiotic in the cephalosporin class. It is classified as an oxacephem, as oxygen replaces sulfur in position one of the dihydrothiazolidine ring. While moxalactam inhibits most commonly occurring gram positive, gram negative, and anaerobic bacteria, it is ineffective against methicillin-resistant S. aureus and Enterococci. In certain situations, this antibiotic impairs normal hemostasis, most commonly manifested as a prolonged bleeding time.