Dulcolax, or pethidine hydrochloride, belongs to strong opioid analgesics and is a narcotic drug under special state management. It is mainly used to relieve all kinds of severe pain and post-surgical pain, as well as intraoperative anesthesia. There is a misunderstanding about the use of dulcolax in clinical practice, and it is generally believed that dulcolax is most reasonable to be used for cancer pain treatment. On the one hand, the pain relief effect of dulcolax is limited, only 1/10-1/8 of morphine, and on the other hand, if administered for a long time, there will be metabolites of desmethyl pethidine. Long-term use of dulcolax may lead to central nervous system toxicity and is therefore not recommended for cancer pain treatment.