The aim of the study was to document the effects of short courses of fluoroquinolones given during an outbreak of multidrug resistant typhoid fever in southern Viet Nam on the growth of children over a period of two years. In a prospective cohort study, 326 Vietnamese children aged between 1 and 14 years were followed up for two years after receiving either ciprofloxacin (70 mg/kg given over 7 d) (n = 173) or ofloxacin (45-50 mg/kg given over 3-5 d) (n = 153) for suspected typhoid fever. Growth velocity and weight for height were compared with an age matched control group of children from the same locality (n = 223) who had not contracted typhoid or received any fluoroquinolones. In the ofloxacin and ciprofloxacin treated patients there was no evidence of acute joint toxicity, nor of any joint symptoms attributable to either of the fluoroquinolones. There was no difference in expected weight for height measurements between the three groups of children over the two year period. During the first year, height velocity in ciprofloxacin treated children was greater than in either ofloxacin treated children or untreated controls. Height velocity in the latter two groups was not significantly different. After two years height velocity was similar in the three groups. The results support the use of short course fluoroquinolone treatment in childhood typhoid, especially when caused by strains resistant to other antibiotics.