Amisulpride is a potent antagonist of dopamine D2 and D3 receptors, both implicated in the emetic response when activated. It is currently used intravenously for the prevention of chemotherapy-induced and postoperative nausea and vomiting (PONV), but this route has a short half-life time of 4 to 5 hours, could be expensive, causes infusion-related pain, and is not available in Brazil. Some of these limitations could be overcome by the preemptive use of an oral formulation. At present, there are no data regarding the use of oral amisulpride for PONV, which is an affordable and painless option with half-life time of 12 hours. We propose a quadruple-blind clinical trial involving patients undergoing gynecological surgery aged 18 years and older, and assessed as being at high risk for PONV according to the Apfel Score (score 3 or 4). The primary outcome of this study is to evaluate complete response to PONV up to 24h, comparing the efficacy of adding 50 mg oral amisulpride as a third antiemetic agent to the standard institutional protocol at the Hospital da Mulher of São Paulo (IV dexamethasone 10 mg + IV ondansetron 4 mg) for laparoscopic surgeries. Secondary outcomes will evaluate (1) nausea, (2) vomiting, (3) nausea and vomiting, (4) use of rescue treatment, (5) overall adverse events, and (6) adverse events.