PURPOSE OF REVIEW: To summarize and reflect over primarily recent epidemiological and randomized controlled trials in opioid-treated chronic nonmalignant pain patients, focusing on effects, side effects, risks and long-term consequences of the treatment. RECENT FINDINGS: In the western world opioids are increasingly being used for long-term treatment of chronic nonmalignant pain. While the long-term benefits of opioids regarding pain relief, functional capacity and health-related quality of life still remain to be proven, studies are emerging that describe serious long-term consequences such as addiction, opioid-induced hyperalgesia, cognitive disorders, and suppression of the immune and reproductive systems. SUMMARY: Much more research is needed concerning long-time effects and consequences of opioid therapy in chronic nonmalignant pain patients; however, some clear warning signals have been sent out within recent years.