According to the WHO guidelines for three-step pain management for cancer pain, the five basic principles of cancer pain medication are as follows 1. Prefer non-invasive route of drug delivery Oral medication has the advantages of non-invasive, convenient, safe and economic. With the research of new dosage forms for pain relief and the different needs of patients for different routes of drug delivery, in addition to the oral route of drug delivery, other non-invasive routes of drug delivery are becoming more and more widely used, such as transdermal patches, rectal suppositories, etc. If necessary, choose the infusion pump continuous subcutaneous infusion route to administer drugs. 2.Medication according to the ladder Medication according to the ladder refers to the selection of analgesic drugs according to the degree of pain from mild to severe, and the selection of analgesic drugs of different strengths in order. Mild pain: the first step of three steps of NSAIDs (represented by aspirin) is preferred; moderate pain: weak opioids (represented by codeine) are preferred, and NSAIDs can be used together; severe pain: strong opioids (represented by morphine) are preferred, and NSAIDs can be used together. The combination of NSAIDs with opioids can both increase the pain-relieving effect of opioids and also reduce the opioid dosage. At the same time, you can choose to use tricyclic antidepressants or anticonvulsant drugs according to your condition. 3.Timely medication Timely medication means that pain medication should be given regularly at prescribed intervals instead of waiting for patients’ needs. 4.Individualized administration Due to individual differences, there is no ideal standard dose of opioid drugs. The dose that can make the pain relieved is the correct dose. Therefore, the choice of opioids should start with a small dose and gradually increase the dose to the ideal dose to relieve pain and no obvious adverse reactions. 5. Pay attention to specific details Patients who use painkillers should be monitored, closely observe the degree of pain relief and physical reactions, and take necessary measures in time to reduce the adverse effects of drugs as much as possible and improve the effect of pain relief treatment.