Around 30% of appendectomies are performed for complicated acute appendicitis (CAA, i.e. cases with perforated appendicitis, extraluminal fecaliths, abscesses, or local or generalized peritonitis). The treatment of these complicated forms involves the following steps: initiation of antibiotic treatment at the time of the diagnosis, appendectomy and post-operative antibiotic therapy that continues for 3 days for localized forms of CAA and for 5 days for generalized peritonitis (according to the guidelines issued by the French Society for Anaesthesia and Critical Care Medicine (SFAR)). The results of a Cochrane meta-analysis published in 2005 suggested that the post-operative infection rate was lower in patients having receiving antibiotic therapy after surgery for AA. When only cases of CAA were considered, the difference was no longer significant. However, it should be noted that the studies included in the meta-analysis are now rather old (published before 1995, with open procedures) and no longer provide valid data for answering this question because most appendectomies (80%) are now performed using laparoscopy. Furthermore, a recent cohort study compared a short (3-day) course of antibiotics with a long course (at least 5 days) in patients with CAA having undergone laparoscopic or open appendectomy. There was no significant intergroup difference in the post-operative complication rate. One can thus legitimately question whether post-operative antibiotic therapy is required after laparoscopic appendectomy for CAA. The purpose of the present study is to evaluate the impact of the absence of post-operative antibiotic therapy on the organ space surgical site infection (SSI) rate in patients presenting with CAA (other than cases of generalized peritonitis) by comparing a group of patients having undergone a conventional strategy of post-operative antibiotic therapy for three days after appendectomy for CAA (the control group) with a group of patients having received a post-operative placebo for three days after appendectomy for CAA (the experimental group). The primary endpoint will be evaluated at one month after randomization.