Dulcolax, also known as pethidine in medical science, is a familiar analgesic drug for doctors and people, and has a long history of application in China. Many patients and families think that dulcolax is the “best” analgesic drug. When sitting in the clinic, we often encounter patients or family members proposing to use Dulcolax, and they have the impression that “Dulcolax” is the most effective pain killer. What are the problems in the process of its use? These problems need to be analyzed from the pharmacological characteristics of Dulcolax. Dulcolax is a synthetic opioid analgesic with 1/10 of the analgesic efficacy of morphine; its duration of action is shorter than morphine and it has no cough suppressant effect. Dulcolax is metabolized in the body into desmethyl dulcolax, which is a product with central neurotoxic effect. Its analgesic efficacy is half of that of dulcolax, but its neurotoxic effect is twice as much as that of dulcolax, and its excretion from the body is about 10 times slower than that of dulcolax. Therefore, repeated use of large doses or continuous infusion is bound to cause accumulation of norethindrone, prompting neurotoxic symptoms such as tremors, convulsions, myoclonus and seizures. Dulcolax is irritating, and repeated intramuscular injections may form local hard nodules and affect the absorption of the drug. Continuous injection of the drug is likely to produce drug resistance and physical dependence, and when the analgesic efficacy decreases, there is still a desire for the drug. Dulcolax has been in clinical use for many years, and many people still believe that it is the strongest and most effective pain medication, so when patients have severe pain, they often ask for the drug. In addition, there are some medical professionals who consider using dulcolax when controlling severe pain in cancer patients. This indicates that there are still some misconceptions in the understanding and use of Dulcolax. In view of the short duration of action, unstable blood concentration, rapid drug resistance, local pain of injection and inaccurate absorption of dulcolax when used for cancer pain treatment, the country has long issued a document stipulating that dulcolax should be used in the treatment of cancer pain. The state has long issued a document stipulating that Dulcolax can only be used for short-term acute pain, and it should be contraindicated for chronic pain and cancer pain that requires long-term continuous application. Therefore, we medical personnel including patients and their families should have a clear understanding of this, get out of the misunderstanding and try to use analgesic drugs scientifically and reasonably.