Opioids are a class of drugs that are commonly used for pain relief, but can also have addictive properties. They work by binding to opioid receptors in the brain and blocking pain signals. Opioids can be prescription medications, such as oxycodone, hydrocodone, and morphine, or they can be illegal substances, such as heroin. The misuse of opioids has become a major public health concern, leading to a rise in overdose deaths and addiction rates. Researchers are studying ways to better understand and treat opioid addiction, as well as develop safer and more effective pain management options.