Purple ecchymosis at the root of thigh may be caused by trauma, thrombocytopenia and anticoagulant drugs, which can be treated with drugs to activate blood circulation and remove blood stasis, or by splenectomy and stopping anticoagulant drugs. 1. Trauma: Trauma to the thigh root leads to rupture of capillaries and extravasation of blood, resulting in purple ecchymosis. Ointment can be used externally to reduce swelling and pain, activate blood circulation and remove blood stasis. 2. Thrombocytopenia: Thrombocytopenia reduces the hemostatic function of the human body, and mild trauma to the root of the thigh can lead to bruises. Treatment can choose corticosteroids to slow down the destruction of platelets, or surgical treatment of splenectomy. 3. Long-term use of anticoagulant drugs: If the patient has a history of myocardial infarction, he may be taking anticoagulant drugs such as warfarin for a long period of time, which may easily lead to bruising at the base of the thigh. Serious cases need to adjust the dose of drugs, or stop using anticoagulant drugs. If the above symptoms occur, it is necessary to consult a doctor in a timely manner, who will give different treatment plans and individualized treatment according to the cause of the disease, do not self-medication.