Patients with symptoms of high prothrombin time may be caused by abnormalities in the coagulation system, drug causes or liver diseases. 1. Abnormalities of coagulation system: patients with abnormalities of coagulation system will lead to high prothrombin time. Abnormalities or lack of coagulation factors in the exogenous coagulation system can lead to high prothrombin time. 2. Drugs: patients taking anticoagulant drugs, such as heparin, can antagonize vitamin K, affecting coagulation function, resulting in patients with high prothrombin time. 3. Liver disease: prothrombin time is usually determined by the level of coagulation factor production synthesized by the liver, patients with liver disease, such as liver failure, cirrhosis, etc., will cause a decrease in coagulation factor production, resulting in high prothrombin time. There may be other reasons for the occurrence of high prothrombin time, and it is necessary to go to the hospital in time for consultation and medication under the guidance of professional physicians.