Painkillers usually take effect about 20-30 minutes after oral intake. The onset of action of painkillers is related to the absorption time in the gastrointestinal tract, and painkillers are generally absorbed into the bloodstream through the gastrointestinal tract in about 20 to 30 minutes after taking them. Common pain medications include non-steroidal anti-inflammatory drugs (NSAIDs) and opioids, such as ibuprofen, celecoxib, parecoxib, as well as drugs such as tramadol and pethidine. It should be noted that pain medication can only play a role in relieving the symptoms of pain, but can not play a role in treating the root cause of the disease, when the patient appears to have pain should be clear cause of the disease and related treatment, not simply with pain medication. The use of medication should be under the guidance of a doctor, not unauthorized use of medication.