Patients are often prescribed opioids after hospital discharge for surgery. However, several studies have shown that at least 3% of preoperative opioid-naive patients continue to use opioids for a long time after surgery. Prolonged opioid use is associated with serious side effects such as physical and psychological dependence, cognitive disturbances and adverse effects on sex hormone balance. Prolonged opioid use should be avoided, if possible. In this article, we summarise the current knowledge of prolonged opioid use after surgery and propose several preventive measures.