In vitro inhibitory tests showed that the minimal inhibitory concentrations(MICs)of norfloxacin,ciprofloxacin, enrofloxacin,gentamycin and chloramphenicol were0.2,0.025,0.1,0.4 and 12.8 mg/L for Salmonella pullorum, respectively Followingtreatment with norfloxacin (50mg/L),ciprofioxacin(50 mg/L),enrofloxacin(50mg/L),gentamycin(50mg/L)and chloramphenicol(500 mg/L)via the drinkingwater for 5 successive days, tbe curative rates of the above five drugsfor S.pullorum infected chicks were 100%,100%,100%,86.7% and 86.7%,respectively.In the S.pullorum infected and untreated group,the mortality ofchicks was 43.3%.There were significantly differenee in weight gains betweenthe gro ups given ciprofloxacin,enrofloxacin and groups given norfloxacin.gentamycin and chloran1phenicol.