Gastrointestinal damage is the most common complication of cyclooxygenase inhibitors, which is characterized by three main features: ① manifested as dyspeptic symptoms, such as dyspepsia, heartburn, nausea, vomiting and abdominal pain. ② endoscopic manifestations of gastrointestinal mucosal damage. Serious gastrointestinal damage such as perforated peptic ulcer or gastrointestinal bleeding requires hospitalization. GI bleeding is more common with aspirin than with ulcers, while non-aspirin cyclooxygenase inhibitors cause more GI ulcers than bleeding. Gastrointestinal damage with conventional cyclooxygenase inhibitors occurs early, is more frequent, and is more harmful. The patient’s symptoms are hidden: due to the analgesic effect of cyclooxygenase inhibitors, most of the patients are asymptomatic when gastrointestinal damage occurs, and only the more serious gastrointestinal damage will appear the corresponding symptoms. Serious consequences: According to statistics, in the United States every year, more than 100,000 patients are hospitalized because of gastrointestinal complications caused by cyclooxygenase inhibitors, and the annual number of deaths reaches 16,500, which is similar to the number of deaths caused by AIDS. Therefore, it is important to prevent the occurrence of gastrointestinal diseases associated with cyclooxygenase inhibitors. 1, the causes of gastrointestinal damage caused by cyclooxygenase inhibitors The main causes of gastrointestinal damage caused by cyclooxygenase inhibitors: ① endogenous prostaglandin synthesis is reduced, thus weakening the protective effect on the gastric mucosa. ② The direct toxic effect of the mucosa of cyclooxygenase inhibitors and their use. (iii) Increased production of inflammatory mediators leukotrienes in the gastrointestinal tract, and neutrophil-mediated gastric mucosal damage. (iv) Helicobacter pylori infection is a high risk factor for peptic ulcer in patients receiving long-term cyclooxygenase inhibitor therapy. 2. Risk factors of gastrointestinal damage caused by cyclooxygenase inhibitors According to the statistical comparison of 1457 cases of patients with gastrointestinal bleeding and 10000 cases of control group in the UK, the relative risk of upper gastrointestinal bleeding caused by cyclooxygenase inhibitors is 4.7 times of that of the patients without cyclooxygenase inhibitors, and the risk of upper gastrointestinal bleeding of patients with a history of peptic ulceration is 13.5 times of that of the patients without a history of ulceration. Prolonged low-dose aspirin use, advanced age, history of bleeding or perforation of gastrointestinal ulcers, alcohol overdose, gender (higher in males than females), use of corticosteroids, use of anticoagulants, high-dose medication, and prolonged use of medication are all risk factors for gastrointestinal tract injury from the use of cyclooxygenase inhibitors. The greater the number of risk factors, the higher the chance of gastrointestinal injury with cyclooxygenase inhibitors. Patients are categorized into four levels according to the number of risk factors they have: low risk (no risk factors mentioned above), moderate risk (1-2 risk factors), high risk (more than 2 risk factors, or the patient is combining steroids, low-dose aspirin, or other antiplatelet drugs), and very high risk (a history of ulcers). 3. Prevention and treatment of gastrointestinal damage caused by cyclooxygenase inhibitors ① Correct diagnosis, strict control of the indications and contraindications of cyclooxygenase inhibitors, and prevention of abuse. Only those who have inflammation should be given cyclooxygenase inhibitors, while those who only have pain without inflammation can be given some simple and effective painkillers to avoid unnecessary long-term use of large doses of cyclooxygenase inhibitors. Simultaneous use of two cyclooxygenase inhibitors does not increase the efficacy of side effects increase, so it is not suitable for the use of compound preparations, it is preferable to use a single component preparation. For peptic ulcer and gastrointestinal bleeding patients are prohibited to use cyclooxygenase inhibitors. Low-risk patients should use drugs and dosage forms that cause less damage to the gastrointestinal tract. Different cyclooxygenase inhibitors in the conventional dose of gastrointestinal injury relative risk is different, diclofenac, sulindac, indomethacin, naproxen, ketoprofen, piroxicam, aspirin, and other cyclooxygenase inhibitors are more dangerous than ibuprofen in the occurrence of serious gastrointestinal adverse events, piroxicam gastrointestinal side effects occur with the highest frequency, the non-selective cyclooxygenase inhibitors in the gastrointestinal injury risk of ibuprofen lowest, and ibuprofen has been shown to remain effective in small doses. Enteric-coated preparations, sustained-release preparations, controlled-release preparations and other dosage forms reduce the gastrointestinal irritation caused by the large amount of ordinary preparations released in a short period of time, and the use of topical dosage forms can avoid the direct stimulation of the drug on the gastrointestinal, and seldom cause visceral damage, but it is only applicable to local anti-inflammatory analgesia.COX-2-selective inhibitors to reduce the side effects on the gastrointestinal tract, the gastrointestinal tract damage of COX-2-selective inhibitors is significantly higher than that of non-selective cyclooxygenase inhibitors. COX-2 selective inhibitors reduce the side effects on gastrointestinal tract, COX-2 selective inhibitors gastrointestinal damage than non-selective cyclooxygenase inhibitors significantly reduced. (iii) Use with caution in the elderly. Gastrointestinal damage from cyclooxygenase inhibitors increases with age, and the relative risk of upper gastrointestinal bleeding is 1.6, 3.1, and 5.6 times higher in the 50-59, 60-69, and 70-79 year olds than in the 20-49 year olds, respectively. Life-threatening gastric and duodenal perforation and bleeding occurred at high rates in the elderly, and deaths associated with cyclooxygenase inhibitors occurred almost exclusively in those older than 60 years. Individuals ≥75 years of age with the other 3 risk factors have a 9% likelihood of developing serious complications in the upper GI tract within 6 months. ④ Different strategies should be used to prevent gastrointestinal injury in the presence of concomitant gastrointestinal risk factors: in moderate-risk patients, NSAIDs should be used in combination with misoprostol or acid-suppressing agents. In high-risk patients, NSAIDs should be avoided; in patients requiring the combination of NSAIDs and antiplatelet agents, proton pump inhibitors or misoprostol should be combined. Very high risk patients, NSAIDs drugs should be avoided, for chronic arthritis treatment, with proton pump inhibitors or proton pump inhibitors and misoprostol combination. Proton pump inhibitors such as omeprazole 40 mg orally once daily can prevent gastrointestinal ulcers that can be caused by taking cyclooxygenase inhibitors. Misoprostol, with its antigastric acid secretion and gastric mucosal protective effect, 400 μg orally twice daily, can treat duodenal and gastric ulcers caused by NSAIDs, guaranteeing the continuation of NSAID therapy, and is also used for the prevention of ulcers caused by NSAIDs. The minimum effective dose should be used in the presence of gastrointestinal risk factors, for short periods of time or intermittently. When patients experience pain, bleeding, signs of intestinal obstruction or changes in bowel habits, the drug should be discontinued and medical attention sought.