Some patients with deep vein thrombosis are discharged from the hospital before the dosage of Warfarin has been adjusted and stabilized, and the discharge medical advice usually requires an outpatient review after one week. At the request of patients, especially those who are unable to return to the hospital for long-term review, the following method is recommended for some reference in adjusting warfarin dosage after discharge: The anticoagulant effect of warfarin is not immediate after oral administration; it takes at least 3 days for oral warfarin to really take effect. The most critical aspect of using warfarin is to adjust the appropriate dose. The dose-response (International Normalized Ratio INR) relationship of warfarin is highly variable and is influenced by many factors and therefore needs to be closely monitored. Therapeutic target values: to achieve prothrombin time (PT) between 20-30sec and national standard ratio (INR) between 2-3 Generally, we start with 2.5mg and take it orally once a day. Warfarin reaches its peak blood concentration 48-72 hours after oral administration, when the effect on coagulation index is most obvious. Therefore, generally after 3 days of oral dosing starting from 2.5mg, we need to draw four coagulation items to observe the prothrombin time (PT) and international standard ratio (INR), if the PT is between 20-30sec and INR between 2-3, then the treatment goal is achieved. If the PT is less than 20sec and INR less than 2, it means that the drug dose has not reached the treatment standard, then increase 1/4 tablet (warfarin increase or decrease, both are subject to 1/4), after 3 days of increase, review the coagulation index, if it reaches the standard, then review after one week, after 2 weeks, after one month; if If the PT is greater than 20sec and INR is greater than 2, it means that the drug dose exceeds the treatment standard, and there is a risk of bleeding, then reduce 1/4 tablet, and after 3 days of reduction, review the coagulation index, if it reaches the standard, then review it after one week, 2 weeks, and one month; if it is still greater than the target value, then continue to reduce The above adjustment method is limited to patients who can fully understand the condition and treatment plan. The disadvantage of warfarin is the risk of relapse if the treatment target is not reached, and the risk of bleeding if the target is exceeded, which requires long-term monitoring of its effect and dosage adjustment. We do not recommend patients to adjust the dosage by themselves, and the best way is to visit the hospital on time during the treatment cycle (6 months) for adjustment. In recent years, rivaroxaban has been gradually used in China for the treatment of deep vein thrombosis with remarkable effect. Its advantages are that it is relatively safe for elderly patients, reduces the risk of bleeding, and is easy to use without repeated blood sampling to recheck coagulation and adjust the dosage; the disadvantage is that it is expensive and difficult for ordinary families to afford. If the indication of rivaroxaban for the treatment of deep vein thrombosis can be approved, and the price can be adjusted downward, it is undoubtedly a gospel for the majority of thrombosis patients.