[en] Background Patients treated with infliximab for Crohn's disease (CD) frequently require intensified dosage due to loss of response. There are scant data regarding the efficacy of shortening the dosing interval to 6 weeks. Aim We sought to investigate the efficacy of a once every 6 weeks' strategy compared with dose-doubling. Methods This work was a multicentre retrospective study of infliximab-treated CD patients who required dose escalation. The clinical outcome of patients treated by intensification to 5 mg/kg/6 weeks (6-week group) was compared with the outcome of patients whose infliximab was double-dosed (10 mg/kg/8 weeks or 5 mg/kg/4 weeks). Results Ninety-four patients (mean age: 29.8 years) were included in the study, 55 (59%) in the 6-week group and 39 (41%) in the double-dose group. Demographics and disease characteristics were similar between the two groups, although patients with re-emerging symptoms 5-7 weeks postinfusion were more likely to receive 5 mg/kg/6 weeks dosing (OR: 3.4, 95% CI: 1.4-8.8, P < 0.01). Early response to dose-intensification occurred in 69% of patients in the 6-week group and 67% in the double-dose group (P = N.S.). Regained response was maintained for 12 months in 40% compared with 29% of the patients respectively (P = N.S.). Conclusion In CD patients who lost response to standard infliximab dose, especially when symptoms re-emerge 5-7 weeks postinfusion, shortening the dosing interval to 6 weeks appears to be at least as effective as doubling the dose to 10 mg/kg or halving the infusion intervals to once in 4 weeks.