Mitral valve replacement refers to mitral valve replacement surgery, which may be dangerous without warfarin for 1 to 2 weeks after surgery. Due to the lesion of one’s own mitral valve, which cannot be relieved by other treatments, mitral valve replacement surgery is needed; as the valves used in mitral valve replacement are biological or mechanical valves, which are foreign to the patient’s organism, they will have an effect on the platelets and leukocytes in the blood, and thrombus will be formed, which is life-threatening. Therefore, after the surgery, biological valves need to take warfarin continuously for about half a year, while mechanical valves need to take the drug for life; not eating warfarin after the surgery will affect the normal coagulation function, resulting in blood clots, endangering the patient’s life; if the patient’s own coagulation function is poor, it may be dangerous about a week after stopping the drug. As each patient’s own situation is different, the time of danger is not the same, it is recommended that patients strictly follow the doctor’s instructions to take warfarin, not to joke with life. If there is any discomfort, it is recommended to go to the hospital for examination in time.