Tranexamic acid, also called coagulic acid, is an anti-fibrinolytic amino acid and is one of the commonly used anticoagulant drugs in clinical practice. It can competitively oppose fibrinogen activation factor, so that fibrinogen cannot be converted into fibrinolytic enzyme, and has inhibited the proteolytic activity of fibrinolytic enzyme. The mechanism of action is similar to that of aminolevulinic acid, which is mainly used for various bleeding caused by hyperfibrinolysis, and also for the prevention of bleeding before trauma or surgery of organs rich in fibrinogen-activating substances, such as prostate, urethra, lung, uterus, adrenal gland and thyroid gland. It is also used for bleeding in the anterior chamber of the eye and severe nasal bleeding, and for minor bleeding in the central system, such as bleeding from subarachnoid emergence and intracranial aneurysms. It is used for the treatment of hereditary angioedema and also for the treatment of patients with hemophilia.