In patients suffering from pulmonary embolism, anticoagulant therapy is the most important treatment. The general anticoagulation therapy starts with intravenous heparin or subcutaneous injection of low molecular heparin, overlapping with an oral anticoagulant, usually warfarin. During anticoagulation therapy, it is important to pay special attention to two aspects, one is to review regularly and the other is not to stop the medication on your own in the middle of the treatment. Why does your doctor want you to have regular reviews? When you take warfarin orally, the prothrombin time (PT) in your body must be prolonged to a certain level in order for the anticoagulation to work and the treatment to be effective. This is now usually expressed using the International Normalized Ratio (INR). In general, the INR should be extended to 2.0-3.0. If the INR value does not reach 2.0, it cannot play an effective anticoagulant role, and when the INR value exceeds 3.0, the anticoagulant effect is not only no longer enhanced, but the risk of bleeding increases, which is the side effect of this drug warfarin. Therefore, it is important to review the INR level regularly during oral warfarin to allow the drug to achieve the best anticoagulant effect. Warfarin is an antagonist of vitamin K, which is a substance that stops bleeding. Warfarin exerts its anticoagulant effect by depleting the body of vitamin K. Therefore, many factors that affect the absorption and metabolism of vitamin K, including certain drugs, foods and some lifestyle habits, can affect the anticoagulant effect of warfarin. In clinical practice, we often encounter people who take oral warfarin together with drugs for gastric diseases such as omeprazole and present to the hospital with hemoptysis and blood in urine. Therefore, if you need to add other drugs while taking oral warfarin, you should go to the hospital and consult with the doctor in time. The length of anticoagulation treatment for patients with pulmonary embolism varies from person to person. For pulmonary embolism caused by surgery, trauma and other factors, treatment is needed for 3-6 months; for patients with unknown source of embolus, treatment is needed for more than 6 months; for patients with recurrence, or combined pulmonary heart disease and long-term risk factors, such as cancer, easy embolism or implanted inferior vena cava filter, the course of treatment is at least 12 months, or even lifelong anticoagulation therapy. The decision of when to stop anticoagulation therapy should be made by the physician based on the patient’s specific situation and the results of the examination. In clinical practice, it is common for some patients to discontinue their medication after encountering some conditions, which is never to be taken, and sometimes even dangerous. A foreign study showed that the risk of recurrence of pulmonary embolism was 16％ in patients who underwent regular anticoagulation therapy, while the risk of recurrence of pulmonary embolism increased exponentially in patients who did not undergo regular anticoagulation therapy. For those patients who are irregularly discontinued and have to undergo anticoagulation again, they cannot simply take oral anticoagulants again on their own, but need to be treated with heparin or low-molecular heparin first, followed by oral warfarin, as in the case of initial anticoagulation. This is dictated by the characteristics of the action of a drug like warfarin. Otherwise the complex interaction of the drug with the coagulation mechanisms in the body can form a clot again. This will not only increase the burden of treatment, but also once again cause a blow to the organism. Therefore, doctors hereby warn patients with pulmonary embolism that anticoagulation therapy must be adhered to the full course of treatment. If there is a need to stop the drug during treatment, such as to extract teeth, surgery, etc., contact your doctor and proceed under his guidance. If bleeding occurs, such as hemoptysis, blood in urine, bleeding gums, bleeding skin, etc., go to the hospital promptly and make adjustment of medication under the guidance of your doctor.