At present, among some doctors and cancer patients, there are three misunderstandings about cancer pain treatment. Misconception 1: Painkillers are used only when the pain is severe Some doctors and cancer patients think that the pain will gradually intensify with the progress of cancer, and they are afraid that if strong painkillers are used at the beginning of the pain, there will be no other painkillers available in the late stage of the disease. In fact, timely application of painkillers is safer, more effective, and requires the lowest strength and dose of painkillers. Cancer pain patients who do not receive effective analgesic treatment for a long time are more likely to have neuropathic pain related neurological dysfunction caused by pain, which is clinically manifested as intractable pain such as nociceptive hypersensitivity and abnormal pain. Myth 2: Pethidine (dulcolax) is the safest and most effective analgesic In fact, the pain-relieving strength of pethidine is only 1/10 of morphine, its oral absorption rate is poor, intramuscular injection of pethidine will make the patient injected with the localization of hard knots and new pain, and its metabolite – nortriptyline has a long clearing half-life, and it has potential neurotoxic and nephrotoxic effects. Therefore, the World Health Organization does not recommend intramuscular injection of pethidine for patients with chronic pain. Myth 3: Long-term use of opioid painkillers will inevitably lead to addiction Many cancer patients think that the use of morphine will lead them to drug dependence (addiction). As a matter of fact, the controlled-release form of potent analgesics currently encouraged for cancer pain patients can avoid large fluctuations in blood concentration while maintaining analgesic effects, and their morphine dose is not sufficient to produce serious adverse effects and the possibility of leading to psychological dependence is also very low. Long-term use of opioid analgesics by patients with cancer pain may require a gradual increase in dosage, which is necessary for clinical pain management, but can be successfully withdrawn when pain is relieved or when necessary, a phenomenon of “physical dependence” on the drug that should be distinguished from so-called “addiction”. It is the non-medical use of opioids that is considered drug abuse, and clinically incorrect administration, such as repeated intravenous injection of large doses of opioids, that can lead to “addiction”. Therefore, special emphasis should be placed on the standardized clinical use of pain medications.