Patients with aspirin-related asthma, allergy to aspirin, active bleeding, and active gastroduodenal ulcers should not take aspirin. 1. Aspirin-related asthma: some patients are particularly sensitive to aspirin, oral aspirin can occur after an asthma attack, such patients can not take oral aspirin. 2. Aspirin allergy: patients who are allergic to any component of aspirin can not take aspirin, otherwise it may lead to severe allergic reactions, and may even be life-threatening. 3. active bleeding: such patients can not take aspirin, aspirin may lead to bleeding symptoms are heavier, and even hemorrhagic shock. 4. active gastroduodenal ulcer: such patients can not take aspirin, aspirin can lead to symptoms of ulcers, and even induce bleeding or even perforation of the ulcer site. Aspirin’s role is to inhibit platelet aggregation, mainly used in the treatment of ischemic cardiovascular and cerebrovascular diseases, the adverse effects of the drug are nausea, abdominal distension, abdominal pain, dyspnea, bleeding and so on. Patients taking aspirin should master the contraindications of the drug, and should be taken under the guidance of a physician to avoid serious complications.