The bruising of the legs may be caused by the following reasons: 1, it may be caused by the patient’s thin keratin, some patients, especially young female patients, have a very thin cuticle, and a slight impact or squeeze on the lower limbs may cause subcutaneous bleeding and bruising; 2, it may be caused by the patient’s poor coagulation mechanism, some patients have liver or blood-related diseases that cause abnormalities in the coagulation mechanism, which may lead to internal bleeding and bruising. Some patients have liver or blood-related diseases, resulting in abnormal coagulation mechanism, which can easily lead to internal bleeding, such as bleeding and bruising when the lower limbs are slightly injured; 3, may be due to increased capillary fragility, which is also common in young women, often due to the lower limbs are slightly squeezed to cause local small capillary rupture, and then produce subcutaneous bleeding and bruising; 4, may also be due to long-term The patient’s long-term use of anticoagulant and antiplatelet drugs, such as warfarin, aspirin and Polivy, may lead to this situation.