Painkillers mostly have side effects of gastrointestinal stimulation or liver function damage, and long-term use may also cause blood clotting dysfunction, so painkillers should not be taken for a long time. Painkillers should be used in accordance with the “three steps” and “five basic principles”. 1. Three steps. (1) Mild pain should choose non-steroidal anti-inflammatory drugs, such as ibuprofen. (2) Weak opioids, such as codeine, can be used for moderate pain, along with a combination of nonsteroidal anti-inflammatory drugs. (3) Strong opioids, such as morphine, or a combination of NSAIDs may be used for severe pain. 2. Five basic principles: oral administration, step-by-step administration, on-time administration, individual administration, and attention to detail. The application of painkillers should be based on the standardized guidance of the doctor to avoid drug abuse.