The most significant effect of cyclooxygenase inhibitors on the hematological system is anticoagulation. Non-selective cyclooxygenase inhibitors inhibit platelet cyclooxygenase-1, reduce thromboxane A2 release, and inhibit platelet aggregation, and their combination with anticoagulants or aspirin significantly prolongs bleeding time. Aspirin needs to be discontinued 7-10 days before surgery to allow platelet function to be restored. Low-dose aspirin is commonly used to reduce the risk of cardiovascular disease. Almost all cyclooxygenase inhibitors can cause aplastic anemia and granulocytopenia. The risk of aplastic anemia was 8.7, 12.7, and 8.8 for pautazone, indomethacin, and diclofenac, respectively, and the risk of aplastic anemia was higher for pautazone, indomethacin, and diclofenac than for other similar drugs. Gastrointestinal bleeding or blood loss should be considered first when anemia occurs in those applying cyclooxygenase inhibitors, and cyclooxygenase inhibitors leading to bone marrow suppression are rare. Use with caution or contraindication in patients with vitamin K deficiency, hemophilia, and pre-existing liver disease.