The bruise appears when the body is touched, indicating that the body’s capillaries rupture and bleeding, bruising, common causes are: a. patients with vitamin C deficiency, because vitamin C has the role of enhancing the density of capillaries, if vitamin C deficiency, the density of capillaries will decline, a slight collision will cause capillary rupture, resulting in bruising. Second, thrombocytopenia patients, no matter what kind of disease caused by thrombocytopenia, the body’s hemostatic function will be reduced, even a slight collision will appear capillary rupture bleeding, resulting in bruising. Third, patients with coagulation dysfunction, no matter which coagulation factor is lacking, coagulation dysfunction, the patient’s clotting time is prolonged, and bruising will occur after a slight collision because of coagulation dysfunction. Therefore, if the body bruises when touched, the function of capillaries, the number and function of platelets and the function of coagulation factors need to be checked to find the cause of bruising on the body.