Cephalosporins are comparable to in mechanism of action, toxicity, and chemically. Cephalosporins have a spectrum of action but are not active against and Listeria monocytogenes.

First generation cephalosporins: cefadroxil (Duricef, Ultracef),cefazolin (Ancef, Defzol), cephalexin (Keflex), cephalothin (Keflin), cephapirin (Cefadyl) and cephradine (generic):---active against cocci, but not active against staphylococcal strains. Excretion of first generation cephalosporins is mainly by and tubular secretion. An example of a drug which blocks tubular secretion is , which can increase antibiotic serum levels substantially. First generation drugs are now only rarely the drug of choice, despite their low toxicity and broad-spectrum of action.