Appendectomy is the standard treatment for acute appendicitis. Since the 1990s, antibiotic therapy has sometimes been proposed as an alternative to immediate appendectomy. How effective are antibiotics in adults with uncomplicated acute appendicitis, and what is the risk of complications? To answer these questions, we conducted a review of the literature using the standard Prescrire methodology. A systematic review with meta-analysis included four randomised trials of antibiotics versus immediate appendectomy, in 900 patients hospitalised with uncomplicated appendicitis. The studies included only patients with few severe symptoms, thus undermining the strength of the results. Antibiotic therapy was usually administered intravenously first, then orally. The antibiotics used were amoxicillin + clavulanic acid, cefotaxime, or a fluoroquinolone. Metronidazole or tinidazole was often added. The total duration of antibiotic treatment was 8 to 15 days. The overall incidence of complications of appendicitis (perforation, peritonitis and surgical wound infections) was 25% in the immediate appendectomy group versus 18% in the antibiotic group. The frequency of perforations and peritonitis did not differ between the groups. All symptoms of appendicitis disappeared, without relapse or rehospitalisation during the first month, in 78% of patients in the antibiotic group. After one year of follow-up, 63% of patients treated with antibiotics were asymptomatic and had no complications or recurrences. In another systematic review of five randomised trials, outcome at one year was optimal in 73% of patients treated with antibiotics alone versus 97% of patients who had immediate appendectomy. In practice, in early 2014, appendectomy remains the first-line treatment for uncomplicated acute appendicitis. In some still poorly characterised patients, the harm-benefit balance of antibiotic therapy is probably better than that of immediate appendectomy. When informed of the risks, some patients are likely to choose antibiotic therapy.