Résumé : In order to define the minimum antibiotic concentration (MAC) of cefadroxil against Haemophilus influenzae, killing curves and kinetic turbidometry were used to study five strains of beta-lactamase negative bacteria and five strains of beta-lactamase positive bacteria. The overall results showed a bactericidal activity of 32 μg/ml, a bacteriostatic activity at 16 μg, and a MAC at 8 μg/ml.