Purple on the soles of the feet may be caused by traumatic bruising, poor blood circulation in the lower extremities, lack of oxygen and other factors. 1. When the foot suffered a recent smash, sprain, fracture and other traumatic injuries, due to capillary rupture bleeding, may form bruises on the soles of the feet, usually take rest, ice, medication and other treatments, if serious, you need to see a doctor. 2. Poor blood circulation in the lower limbs is mainly due to cold and frostbite, disease and other two conditions. When the feet are cold or even frostbite for a long time, the blood circulation will be slowed down, and the skin of the feet will turn purple, so you should pay attention to keep the feet warm and dry, and consult a doctor in time, and in extreme cases, you need to amputate the limbs. 3. When suffering from deep vein thrombosis, lower extremity arterial stenosis, will lead to lower extremity blood circulation obstacles, resulting in purple feet, numbness, should seek medical attention to alleviate the symptoms of ischemia and identify the cause of the disease. It should be noted that diabetic patients’ lower limbs are severely affected by high blood sugar levels, and often suffer from narrowing and stiffening of blood vessels, resulting in purple feet. In the presence of asphyxia, severe cardiopulmonary disease and hypoxia, extremities such as the feet may turn purple and require prompt medical attention.