Since the description of the concept of balanced analgesia in the early 90's, the combination of different analgesic drugs and/or analgesia techniques is part of the standard management of postoperative analgesia. A recent survey conducted in France by Fletcher et al. showed that patients often received one or more NOA associated with an opioid. The benefit and risk of the use of opioids associated with NOA were recently reassessed as part of a formal recommendation of experts and detailed in a recent review. The analysis of the literature reveals a lack of comparison of the combinations of NOA with morphine for postoperative analgesia. For example, paracetamol and morphine in combination does not always allow a significant morphine-sparing effect compared with morphine alone and does not reduce the incidence of morphine side effects. A number of definitive answers has therefore yet to be found: Does NOA -morphine association allow an effective morphine-sparing effect? Is there an interest in prescribing several NOAs in association? If yes, what are the most interesting combinations in terms of morphine-sparing effect and safety?