Morphine is often the best choice for pain relief in advanced cancer, especially for oral extended-release preparations, which are easier to apply. Morphine has many side effects. Clinical use of morphine should pay attention to the following issues: 1. Start with a small dose, preferred dose 5-10mg. once in 12 hours. 2, preferred oral administration. If there is intestinal obstruction, vomiting, unconsciousness, etc., can be switched to topical or subcutaneous, intramuscular or intravenous administration. 12 hours once. The subcutaneous dosage should be 1/3 of the oral dosage. 3, renal insufficiency of patients, due to the accumulation of morphine metabolites, morphine dose should not be too high, the dosing interval should be extended. 4, a regular increase in the amount of medication. The vast majority of patients in the range of 5-60mg selection, gradually increase the amount until the pain relief. 5, pain patients with morphine during if given radiotherapy, chemotherapy, pain symptoms improve, can reduce the amount of morphine 1/2, but can not stop the drug. After stopping radiotherapy and chemotherapy, pain aggravation, can increase the dosage of morphine 2/3. for patients who are not given radiotherapy and chemotherapy, continuous pain, morphine dose selection in the range of pain control. 6, generally need to take laxatives at the same time, to prevent constipation. Constipation is a common side effect of morphine-based analgesics, plus the fact that patients with advanced cancer have less activity, less food and less fiber, which aggravates the occurrence of constipation. Commonly used laxatives are: senna, magnesium hydroxide, liquid paraffin, magnesium sulfate, etc. 7, nausea, vomiting After taking morphine about 50-60% of patients have varying degrees of nausea, vomiting, can be used to extirpate, vitamin B6, mepiquat chloride, etc.. 8, drowsiness After taking morphine, some patients have different degrees of drowsiness and dizziness, which can occur after the first use or after repeated use, and can be reduced by reducing the drug dose or extending the time of administration. 9, respiratory depression is a potentially serious complication in the process of using morphine. Usually occurs in patients who use morphine in excessive doses. When respiratory depression occurs, 1:10 naloxone dilution can be used for slow intravenous infusion. Tracheotomy in comatose patients. 10, acute poisoning manifested as respiratory depression, coma, constricted pupils and digestive tract spasm. Treatment is with the opioid antagonist naloxone. Naloxone can prevent and replace the opioid-like substance from binding to the receptor, blocking its effect and rapidly eliminating the symptoms of poisoning. 11. Physical dependence and drug resistance Physical dependence and drug resistance can occur during the use of opioids, which are normal reactions during the use of such drugs. Physical dependence refers to the withdrawal syndrome that occurs when treatment is suddenly stopped. Drug resistance refers to the repeated use of drugs, drug effectiveness decreases, the need to increase the drug dose or shorten the dosing interval, in order to maintain the original effect. 12, mental dependence that is the so-called addiction problem. Clinical observation and research have found that morphine used for cancer pain treatment will not produce drug addiction if the dose is increased or decreased regularly according to the degree of pain.