Painkillers are also known as analgesic drugs. These medications can be used according to different pain levels. Commonly used analgesics mainly include non-steroidal anti-inflammatory analgesics, opioid analgesics and narcotics. 1.Non-steroidal anti-inflammatory analgesics are the most widely used class of analgesic drugs, which have the effect of reducing the release of analgesic substances and producing analgesia. The usual application of ibuprofen, diclofenac sodium, celecoxib these drugs are typical representatives of this class of drugs, these drugs not only have analgesic effect, but also have anti-inflammatory effect. 2. Opioid analgesics, which act on specific opioid receptors in the body, which are mainly located in the brain and spinal cord. Many oral opioids are used for the treatment of chronic pain, and relatively more are used codeine, dihydrocodeine and morphine. These drugs can be addictive because they act on the central nervous system, which is why they are limited to a certain range of pain treatment. 3, narcotics is actually also a class of analgesics, but the usual occurrence of pain is rarely used, mostly due to disease requires surgery or other analgesic purposes used. Lidocaine is a typical representative of this type of drug and is most widely used. However, this type of drug can not be used in excess, easy to cause local anesthetic poisoning, allergies can not be used, which can be life-threatening. With the advancement of medical and pharmaceutical technology, it is believed that more effective and safe drugs for pain treatment will be available.