Since the 1960's, intraoperative administration of opioids is considered a keystone of anesthesia as well as hypnotics and muscle relaxants. Synthetic opioids were introduced to achieve hemodynamic stability during anesthesia. They allow an inhibition of the sympathetic system without cardiovascular collapse and histamine release. Since then, anesthesia has changed from inhalation to multimodal anesthesia with lower doses of hypnotic. In 2017, the intraoperative objectives of hypnosis, hemodynamic stability, immobility and anticipation of postoperative analgesia can be achieved without opioids. Moreover, opioid administration consequences are neither scarce nor benign for the patient. Perioperative opioids are associated with nausea and vomiting, sedation, ileus, confusion/delirium, respiratory depression, increased postoperative pain and morphine consumption, immunodepression, hyperalgesia and chronic postoperative pain. Among these complications, hypoxemia, ileus and confusion/delirium are the most frequent.