Constipation is one of the common symptoms of cancer patients, and about 70% of advanced cancer patients have constipation complaints. The main causes of constipation are: tumor itself (directly and indirectly), old age, declining gastrointestinal function, low food intake, low crude fiber in food, low activity, dehydration, nausea and vomiting, etc.; application of chemotherapy drugs, especially neurotoxic drugs (vincristine, cytarabine, capecitabine, paclitaxel), antiemetics, 5-HT3 receptor antagonists, opioids, painkillers, etc. are also important causes of constipation. Painkillers are also important causes of constipation. Clinically, we have found that the use of opioids in patients with cancer pain can cause constipation to varying degrees, which occurs not only at the beginning of opioid use, but also persists throughout the course of opioid therapy, making it a difficult problem to encounter in analgesic treatment. Therefore, the prevention and treatment of constipation is particularly important. Preventive measures Appropriate lifestyle modifications, such as intake of high-fiber diet, appropriate amount of water, moderate increase in activity, and good bowel habits can help prevent the occurrence of constipation; minimize the use of drugs that cause constipation, and if they must be used, monitoring should be strengthened and consideration should be given to the prevention of constipation; patients using opioid drugs should receive preventive laxative medication at the same time. What kind of drugs and methods are used to treat constipation in cancer patients depends on the assessment of the degree of constipation and the selection of drugs according to the severity. Stimulant laxatives (colonic light laxatives). These drugs, or their metabolites in the body, stimulate the intestinal wall and increase intestinal peristalsis, thus promoting the excretion of stool. These drugs include phenolphthalein, castor oil, senna, rhubarb, and bixarcoma. Adverse effects are abdominal cramps, mostly dose-related. Small amounts before meals and slightly larger amounts at bedtime can be used to reduce this discomfort. Osmotic laxatives (small intestinal light laxatives). Including disaccharide (lactulose), mannitol, sorbitol, etc., in addition to salt laxatives (magnesium sulfate, etc.). Lubricating laxatives. Including mineral oil, glycerin suppositories, etc., can play a role in softening stool, but long-term use may lead to the loss of fat-soluble vitamins, so the use of such drugs, should avoid meal times, and pay attention to intermittent replacement of other laxatives. Stool softeners. Commonly used are honey, hemp nut laxatives, docusate sodium sulfate (DSS), lactulose, polyoxyethylene propylene, etc., of which DSS is a surfactant that softens stool and reduces the surface tension of stool, thus allowing water to penetrate into the stool. Volumetric laxatives. These include glucosinoglycan, methylcellulose and psyllium, and Tongtai capsules, which treat constipation by increasing the volume of stool and softening it, and are likely to cause abdominal distension and other discomfort with long-term use. Gastric stimulants. Including dopamine receptor antagonists and 5-HT4 receptor agonists. Microbiological agents are mainly used to correct intestinal flora imbalance, improve the microecology of the body, promote intestinal peristalsis and thus improve the symptoms of constipation, commonly used are bifidobacteria and bifidobacterium triad. Combination medication is a clinically accepted treatment method, which can solve the problems of multiple links at the same time and effectively relieve opioid-induced constipation. In addition, enema therapy is the last treatment method patients want to use, but in some patients with constipation without timely prevention and treatment and in some patients with chronic illnesses of frailty and old age with intractable constipation, enemas are sometimes unavoidable.