The mode of administration and onset of action of different forms of pain medication vary. Oral pain medications usually take effect in 30-60 minutes; intramuscular pain medications take effect faster, about 10-15 minutes; sublingual pain medications can also take effect in about 15 minutes. There are also more types of painkillers, and the more common ones are common painkillers, such as NSAIDs, including aspirin, ibuprofen, loxoprofen and other common painkillers, which are suitable for mild to moderate pain. Opioid painkillers are addictive, such as morphine and dulcolax, etc. Such drugs have a rapid onset of action and can provide rapid relief of severe pain by means of intramuscular injection, which are suitable for pain caused by kidney cancer and liver cancer, and can improve the quality of life of cancer patients in the late stage. Since most pain medications can stimulate the mucous membrane of gastrointestinal tract, patients must be under the guidance of professional doctors when taking pain medications to avoid serious adverse reactions.