Résumé : The in vitro activity of drugs currently used in the treatment of diarrhea against 595 enteropathogens from worldwide sources was compared with that of six newly developed antibiotics, ciprofloxacin; norfloxacin; ofloxacin; aztreonam; HR810, an expanded-spectrum cephalosporin; and RU28965, a new macrolide. In contrast with ampicillin and chloramphenicol, trimethoprim-sulfamethoxazole showed an excellent activity against all of the enteropathogens tested, except Campylobacter species. Ciprofloxacin had the highest activity, with an overall 90% MIC of ≤ 0.097 μg/ml, except for Campylobacter species (0.39 μg/ml). Unlike other cephalosporins, HR810 showed a satisfactory activity against Campylobacter species (90% MIC of 3.12 μg/ml). RU28965 was three times less active than erythromycin against Campylobacter species.