In South Viet-nam, typhoid fever remains a considerable intestinal infection. Between 1990 and 1993, among 15 districts in the South of the country, a total per year of 3,853 to 9,179 cases was registered: from 8 to 31 led to death. Recently a large epidemic of typhoid fever broke out in the An Minh district (territory of KiênGiang, South Viet-nam), affecting 3,049 people and bringing on two cases of death. Among the 574 blood samples, 266 strains of S. Typhi, 22 S. Paratyphi A and 2 S. Choleraesuis have been isolated. Our investigations on the spot led to some epidemiologic and clinical reflexions and enabled us to estimate the effectiveness of quinolones (?) in the treatment for typhoid fever. The epidemic may be ascribed to different causes: lack of pure water supply in rural area; fecal pollution caused by inhabitants of this endemic area defecating directly in the waterways; ingestion of contaminated food, especially vegetables sprayed with polluted water; quite low level of public sanitation and individual hygiene. Clinically, the disease consists in prolonged fever, with digestive disorders (anorexia, diarrhoeae, diffuse abdominal aches). Splenomegalia and hepatomegalia are inconstant. The dissociation of the pulse from the temperature is not frequent and the rosy spots are rare. The antibiogramm applied on the isolated strains of S. Typhi revealed their resistance (R) to usual antibiotics (chloramphenicol, ampicillin, Bactrim), but S. Typhi is very sensitive to quinolones (ofloxacin, fléroxacin, R = 0).(ABSTRACT TRUNCATED AT 250 WORDS)