Aprepitant is actually recommended in the prevention of nausea and vomiting induced by high emetic risk chemotherapy using cisplatin. We performed an observational prospective study on 101 patients evaluating the efficacy of aprepitant in the clinical conditions of use of cisplatin, out of context of clinical trial. We did not perform any intervention on the choice of anti-emetic treatment by the clinicians. Data on anti-emetic treatments were collected from prescriptions by a pharmacist after prior consultation with a medical doctor. Inclusions were closed when we lay 50 patients who received aprepitant associated to standard anti-emetic treatment (ondansetron and prednisolone) and 51 patients who received standard anti-emetic treatment. We observed a significant positive effect of aprepitant in the prevention of acute (84 vs 74.4 %, P = 0.24) and delayed vomiting (84 vs 60.8%, P = 0.009). But there was not a significant difference between the two groups regarding the prevention of nausea and the rate of complete response (absence of nausea and vomiting during five days).