Background: From November 2013 to May 2014, we conducted a randomised, single-blind study on the value of dexamethasone prophylaxis in the occurrence of postoperative nausea and vomiting in ENT surgery at the Gabriel Toure University Hospital in Bamako. This study was based on the analysis of pre-anaesthetic consultations, anaesthesia records, postoperative treatment records and patient questioning.Objectives: The aim was to study the interest of Dexamethasone in the prevention of PONV, through the description of the characteristics of PONV, the determination of the risk of their occurrence, and the analysis of their risk factors in relation to Dexamethasone prophylaxis.Results: A total of 158 patients were enrolled; 43 patients had PONV, i.e. an overall incidence of 27.22%; of which 35.4% (28/79) in the absence of prophylaxis (Group B) versus 19.0% (15/79) with Dexamethasone prophylaxis (Group A).Key words: PONV (postoperative nausea and vomiting), prophylaxis, Dexamethasone, risk of occurrence, incidence.