About 50% or more of tumor patients will have varying degrees of pain. Seventy-five percent of patients with advanced tumors have varying degrees of pain. In fact, about 50% to 80% of tumor patients’ pain cannot be effectively controlled. In general, cancer pain should be firstly diagnosed and then treated by appropriate methods. At present, the pain of cancer patients is usually divided into four categories internationally: (1) pain directly caused by cancer; (2) pain related to cancer; (3) pain related to cancer treatment; (4) pain not related to cancer such as gout and arthritis that the patient originally had. The so-called three-step approach to cancer pain treatment is to select the appropriate analgesic according to the degree and cause of the patient’s pain after a correct assessment of the nature and cause of cancer pain, i.e. for patients with mild pain, analgesics of antipyretic type should be mainly used; for moderate pain, weak opioids should be used; for severe pain, strong opioids should be used. Note that the use of analgesics should be increased step by step from weak to strong. The main principles of drug treatment for cancer pain (a) Oral drug administration Oral drug administration route should be chosen to avoid traumatic drug administration route as far as possible, so as to facilitate long-term drug use by patients. Especially for strong opioids (such as morphine tablets and syrups), proper oral administration rarely produces mental dependence (addiction) or physical dependence (<1%). This is because what cancer patients require is analgesic effect rather than mental enjoyment. At the same time, oral morphine does not meet the needs and effects of drug users. (b) Timely administration Pain medication should be given regularly "on time" (e.g., every 3-6 hours) rather than "on demand" - only when the pain is present. (iii) Stepwise dosing Stepwise treatment Drugs Mild pain Non-opioid analgesics are adjuvant drugs Moderate pain Weak opioids are non-opioid analgesics ± adjuvant drugs Severe pain Strong opioids are non-opioid analgesics ± adjuvant drugs (iv) Dosing should be individualized, i.e., attention should be paid to the actual efficacy of the specific patient. The dosage of pain medication should be from small to large according to the patient's needs until the pain disappears. The dosage should not be too restrictive, resulting in underdosing. The correct and appropriate application of adjuvant medications can provide rapid and complete long-term relief of pain. Under the careful guidance of the doctor, the appropriate addition of sedative and anti-anxiety drugs can stabilize the patient's mood and significantly enhance the analgesic effect.