The susceptibility of 424 bacterial isolates causing diarrhoea were tested by agar dilution technique on Mueller-Hinton Agar against amoxicillin, ampicillin, ceftriaxone, chloramphenicol, co-trimoxazole, ciprofloxacin, doxycycline, norfloxacin and ofloxacin. The bacterial species included were Aeromonas hydrophila, Edwardsiella tarda, Pleisomonas shigelloides, Salmonella spp., Shigella spp., Vibrio cholerae and Vibrio parahaemolyticus. The most active compounds were the fluorinated 4-quinolones studied, that is, ciprofloxacin, norfloxacin and ofloxacin, and ceftriaxone. The other antibacterial agents were considerably less active; a substantial portion of tested isolates were resistant to them.