Background.Shigella dysenteriaetype 1 (Sd1) dysentery is associated with serious morbidity and mortality. Treatment is either costly or complicated by the emergence of bacterial resistance. This study compared the efficacy and safety of short course (3 days) and standard course (5 days) oral ciprofloxacin in children with Sd1 dysentery.Methods.A multicenter, randomized, double blind, controlled clinical trial. Children between 1 and 12 years of age with Sd1 dysentery were randomized to receive oral ciprofloxacin suspension 15 mg/kg every 12 h for 3 days followed by placebo for 2 days or ciprofloxacin suspension for 5 days. Treatment success was defined as either resolution of illness or marked improvement on Day 6 of study. Bacteriologic cure was defined as failure to grow Sd1 on a stool sample collected on Day 6. Clinical assessments and joint examinations were performed at baseline, at discharge and 2 weeks later.Results.Of 253 patients enrolled 128 were assigned to short course ciprofloxacin and 125 to standard course ciprofloxacin. The success rates were 65 and 69% for short and standard course ciprofloxacin, respectively. All patients had bacteriologic cure, and all Sd1 isolates were susceptiblein vitroto ciprofloxacin. No bacteriologic relapses occurred during the study period. Eight patients reported arthralgia. All patients had normal joint function including at follow-up.Conclusion.In this study twice daily ciprofloxacin for 3 days achieved clinical cure rates similar to those for the same dosage given for 5 days in children with Sd1 dysentery.