PURPOSE: This study included all patients treated at the University Hospital of Geneva for a first episode of uncomplicated diverticulitis. Risks of recurrence and treatment failure were evaluated by comparing the results between short-course and long-course intravenous (IV) antibiotic therapy groups. METHODS: The records of all patients hospitalized at our facility from January 2007 to February 2012 for a first episode of uncomplicated diverticulitis (Hinchey Ia), as confirmed by computed tomography, were prospectively collected. We published an auxiliary analysis from this registered study at Clinicaltrials.gov (identifier number: NCT01015378). Two groups of patients were considered: one received a short-course IV antibiotic arm (ceftriaxone and metronidazole) for up to 5 days (followed by 5 days of oral antibiotics); the other received a long-course IV arm between days 5 and 10. The primary outcome was the recurrence-free survival time. RESULTS: Follow-up was completed for 256 patients-50% men and 50% women, with a median age of 56 years (range, 24-85 years). The average follow-up was 50 months (range, 19-89 months). Of the 256 patients included in the study, 46 patients received a short-course IV antibiotic treatment and 210 received a long-course treatment. The recurrence-free survivals were very similar between the two groups, which was supported by a log rank test (P = 0.772). Four treatment failures, all in the long-course IV antibiotic treatment group, occurred. CONCLUSION: Treatment of diverticulitis with a short IV antibiotic treatment is possible and does not modify the recurrence rate in patients with uncomplicated diverticulitis.