Fibrinogen is a protein synthesized by liver cells with coagulation function, which can promote platelet aggregation, smooth muscle endothelial cell growth, proliferation and contraction, increase blood viscosity and peripheral resistance, cause endothelial cell damage, and thus promote red blood cell adhesion and thrombus formation. Common clinical pathological factors that cause low fibrinogen include: i. Excessive consumption resulting in reduced plasma levels, such as DIC. ii. Systemic enhancement of fibrinolysis, such as primary hyperfibrinolysis, etc. Third, decreased synthesis of fibrinogen, such as severe hepatitis and cirrhosis. The decrease of fibrinogen can easily cause bleeding disorders, so if the fibrinogen is low, it is recommended to clarify the specific cause and find the cause before targeted treatment. If it is a physiological decrease, it is recommended to recheck the coagulation function after a week, which can generally return to normal.