Abstract: Gentamicin is an aminoglycoside bactericidal antibiotic used in therapy mainly against Gram negative bacteria. Cefotaxime is a semisynthetic broad spectrum bactericidal cephalosporin antibiotic and used against Gram positive and Gram negative bacteria. Metronidazole is an antimicrobial drug used in treatment of protozoal and anaerobic bacterial infection which may be administered with Gentamicin and/or Cefotaxime in the treatment of mixed infections caused by anaerobic and aerobic organisms. Combination therapy has complementary mechanisms of action.