Patients usually require anticoagulation therapy after valve surgery. Patients with mechanical valve replacements require lifelong warfarin postoperatively, and patients with bioprosthetic valves and valvuloplasty (using a prosthetic ring) take warfarin for 3-6 months postoperatively. Control of the International Normalized Ratio (INR) of 2.0-3.0; a high INR can cause bleeding and a low INR can cause thrombosis, both of which can result in serious anticoagulation-related complications and are important for the patient’s postoperative quality of life and long-term survival. Blood tests for prothrombin time (PT) are drawn daily during post-operative hospitalization, and weekly rechecks are recommended after discharge. Warfarin dosage is adjusted according to INR results, with an increase if less than 2.0 and a decrease or discontinuation if greater than 3.0, with adjustments ranging from one-quarter to one-half tablet. If the result is between 2.0 and 3.0 for 2 consecutive weeks, it can be extended to 1 review in 2 weeks. And so on, but the longest interval between blood tests should not exceed 2-3 months. At present, domestic warfarin is 2.5mg per capsule, and most patients can reach the target value by taking 1-2 capsules once a day for maintenance. A small number of patients taking more than 2 capsules still do not meet the target, it is recommended to switch to imported warfarin, 3mg per capsule, on the one hand, the single capsule dose is larger, on the other hand, absorption and utilization may be better. If the target is still not achieved, do not blindly increase the dose at this time, you can add aspirin 0.1 daily for anticoagulation. There are a few patients with bleeding tendency, INR>2.0 means bleeding, for these patients need to reduce the anticoagulation requirement appropriately, INR control around 1.8 is acceptable. In addition to regular review of PT while taking warfarin, you should be alert to some bleeding symptoms, such as spontaneous petechiae on the skin, nasal bleeding, bleeding from the corners of the eyes, black stool, hematuria, and excessive menstruation, etc. In case of these conditions, blood tests or discontinuation of the drug should be performed as soon as possible. At the same time, drugs and diet can also affect the anticoagulant effect of warfarin, such as cortisone, acetylsalicylic acid, pautazone, tetracyclines, sulfonamides, etc. can enhance its anticoagulant effect, while the dosage of warfarin needs to be reduced appropriately when using the drug. And phenobarbital, Grumet and phenytoin sodium will weaken its anticoagulant effect. Green vegetables including bok choy, spinach, asparagus, kale and peas are rich in vitamin K, which will weaken the anticoagulant effect of warfarin. It is recommended to have a balanced diet of green vegetables while taking warfarin. The warfarin dose also needs to be increased appropriately when weight gain and physical fitness is enhanced. Warfarin should be taken once a day at regular intervals, and if forgotten should be taken once immediately upon discovery, and gradually moved forward to the prescribed time. The prothrombin time (PT) test is usually carried out in secondary hospitals, and blood should be drawn in person at the hospital.