D-dimer is a product of the degradation of fibrin in the blood, and its increase means that the blood in the body is in a hypercoagulable state, suggesting a tendency to form blood clots. Second, physical factors, such as pregnancy, surgery, and prolonged bed rest. The third is disease, such as pulmonary embolism, hypercoagulable malignant tumors, abnormalities of the blood vessel wall such as atherosclerosis, and increased blood viscosity such as burns. The fourth other factors, such as oral contraceptives. In the diet, it is recommended to reduce the consumption of fatty foods, more fresh vegetables and fruits, as well as regular review in the hospital, plus medication if necessary.