['Fluoroquinolones reduce occurrence of fever in adult cancer patients who develop neutropenia, but there has been no randomized controlled trial in children, and there are only a few studies considering resistance in intestinal floral after ciprofloxacin has been used.', 'Children younger than 18 years with acute lymphoblastic leukemia or lymphoma scheduled to undergo chemotherapy were randomized to receive oral ciprofloxacin 20mg/kg/day or placebo from the beginning of their chemotherapy. Rectal swab cultures were taken before and at 1 and/or 2 weeks after the intervention.', 'Of the total of 95 patients, 45 and 50 patients received ciprofloxacin and placebo, respectively. Of the 71 patients who developed neutropenia, the proportion of children who developed fever was significantly lower in the ciprofloxacin group than in the placebo group (17/34 [50.0%] versus 27/37 [73.0%]; absolute difference in risk, -23.0%; 95% confidence interval: -45.0% to -0.9%; P = 0.046). Ciprofloxacin significantly reduced the occurrence of febrile episodes in patients with acute lymphoblastic leukemia in the induction phase of chemotherapy, but not in patients with lymphoma or in the consolidation phase of chemotherapy. Adverse effects were not different between the groups. After intervention, the percentages of Escherichia coli and Klebsiella pneumoniae susceptible to ciprofloxacin were significantly lower in the ciprofloxacin group.'] Does ciprofloxacin reduce occurrence of fever in children with acute leukemia who develop neutropenia during chemotherapy?