This paper reports the changes in susceptibility of Salmonella spp. to 32 antimicrobial agents from 1959 to 1988. The clinical observation on the treatment of typhoid fever caused by drug-sensitive and resistant strains of S. typhi arc also reported. Resistant Salmonella began to appear from the year of 1986. The in vitro studies indicated that drug-resistant S. typhi were resistant to commonly anti-typhoid agents such as chloramphenicol

SMZ/TMP

ampicillin and other drugs

but were very sensitive to new quinolones and the third generation cephalosporins. The .therapeutic effects correlate well with the in vitro sensitivity tests. Typhoids caused by drug-sensitive strains responded well when treated with chloramphenicol

SMZ/TMP or ampicillin

while those caused by resistant strains only responded well to norfloxacin or its combi-nation with other drugs