After reading with great interest the article entitled: “Non-vitamin K antagonist oral anticoagulants (NOACs) do not increase the risk of hepatic impairment in patients with non-valvular atrial fibrillation: insights from multi-source medical data” authored by Zhi-Chun Gu et al. and published by Reviews in Cardiovascular Medicine, we would like to add the following thoughts. Oral anticoagulants are generally accepted in patients with non-valvular atrial fibrillation to prevent thrombosis and stroke. Since anticoagulants are taken daily for many months in these patients, we cannot rule out chronic poisoning and the development of liver failure. But another complication is just as likely, that being bleeding. Thus, the determining risk factor for the health of patients with a prolonged course of oral anticoagulants is hypofunctional activity of the blood coagulation system, which remains at the same level throughout the course of treatment. At the same time, it is the activity of the blood coagulation system that is an important and very sensitive link of adaptation to various external and internal factors, including anticoagulants. The fact is that regular and prolonged oral use of anticoagulants is likely to develop and tolerance to them. That is why it is necessary to carefully study the relationship between the dose of oral anticoagulants, the duration of pharmacotherapy and the development of thrombosis (bleeding) in patients with non-valvular atrial fibrillation.