Pain, which is classified by modern medicine as the fifth vital sign after breathing, pulse, blood pressure and body temperature. Many diseases are initially manifested by pain, back pain, neck pain, headache, joint muscle pain …… all kinds of pain often accompany people throughout their lives, painkillers have become a lifesaver that people expect to relieve pain. However, painkillers are a “double-edged sword”, reasonable use can indeed play a role in reducing pain; on the contrary, they can cause serious damage to human health and even endanger life. Recently, I was invited to an outside hospital to consult a middle-aged patient with advanced cancer pain who had been suffering from addiction to intramuscular dulcolax (pethidine) for the past 3 months or so. The reason for this was the failure to follow the three-step pain relief principles issued by the World Health Organization in 1986. In fact, cancer pain patients should follow the following principles to relieve pain: pain medication must be given on time and not on demand. They should be given at fixed intervals, such as once every 8 hours, and controlled-release tablets should be given once every 12 hours, instead of giving them again when pain occurs, so as to ensure effective pain control. It should also be administered orally as much as possible. Those who are inconvenient can choose to administer the drug through the rectum and anus or through the skin. Fourth, individualized medication is needed. The sensitivity of each person to the drug varies greatly among individuals, and should start with a small dose and gradually increase to the optimal dose for the patient to feel effective pain control. Of course the most commonly taken in people’s daily lives are non-steroidal anti-inflammatory painkillers, represented by aspirin, such as ibuprofen, anti-inflammatory pain, paracetamol, celecoxib, etc. Non-steroidal anti-inflammatory painkillers are widely used, effective, used for common pain in general, and do not have addictive properties. Currently NSAIDs are one of the most used drug classes worldwide. With the increase in their use, the safety of these drugs has become a growing concern. Most of the adverse reactions caused accordingly are caused by this class of painkillers. Therefore, doctors recommend that painkillers should not be used indiscriminately and should be taken under the guidance of a professional doctor. The following principles should be observed: 1. Do not take painkillers at your own discretion. When you have pain and discomfort, do not buy drugs from the pharmacy and take them by yourself, but go to the hospital for specialist (such as pain department) consultation and examination, so as to avoid covering up the real disease and delaying the treatment. At the same time, doctors can choose the appropriate painkillers according to the specific cause of the disease. 2.Appropriate combination of drugs. For patients who have peptic ulcer or history of gastric bleeding and must use painkillers, gastric mucosal protectors can be used in combination and taken after meals to reduce damage to the gastrointestinal tract. Suppositories applied transrectally or creams (ointments) applied transdermally may be used if there is a greater risk of gastric bleeding as assessed by a physician. It is forbidden to use two or more similar painkillers at the same time. 3.Master the contraindications of drugs. Peptic ulcer or bleeding, hepatic and renal insufficiency, severe hypertension and congestive heart failure, hematocrit, pregnancy and lactating women. 4. Alcohol or strong tea should not be consumed during the medication period, otherwise it will affect the absorption and metabolism of the drug. It is not advisable to combine with anticoagulants (such as warfarin), otherwise it may increase the risk of bleeding. Therefore, it is important to adhere to the medication principles of taking painkillers rationally, to minimize and avoid misuse, and to bring into play the best painkilling effect of painkillers, so that painkillers can better serve the physical and mental health of people.