Clopidogrel has side effects such as bleeding tendency when taken for a long period of time, and side effects such as gastrointestinal reaction, rash, thrombocytopenia, leukopenia, etc. can also occur. 1. Clopidogrel is an antiplatelet drug with significant antiplatelet aggregation effect, which can be used in the treatment and prevention of coronary heart disease and cerebral ischemia, and also used in the anticoagulation process after stent implantation, joint replacement and other surgeries, which has the effect of preventing thrombosis. 2. Clopidogrel has anticoagulant effect, which may lead to bleeding in other parts of the body, such as nasal bleeding, oral bleeding, subcutaneous bleeding and so on, and even gastric bleeding, intracranial bleeding and other adverse reactions. Therefore, long-term use of clopidogrel should be regularly monitored coagulation function, once the occurrence of subcutaneous petechiae, oral or nasal bleeding, vomiting blood and black stools, immediately seek medical attention, reduce the dosage or stop the drug as appropriate. Some patients also experience gastrointestinal reactions such as diarrhea, nausea, vomiting, skin rashes and other skin lesions, thrombocytopenia, leukopenia and other side effects when taking clopidogrel. 3. This drug is contraindicated in people who are allergic to clopidogrel, patients with severe liver damage, and people with active pathologic bleeding (e.g., peptic ulcer or intracranial hemorrhage). The incidence of the above side effects of clopidogrel is low, and the occurrence of serious side effects can usually be avoided by correct use of the drug and regular review and monitoring of coagulation function. The therapeutic benefits far outweigh the risks, and the drug should be used in accordance with the doctor’s instructions and should not be discontinued on its own. However, if there are contraindications to the use of the drug, it should be avoided.