There are many reasons for purple toenails, which can be generally divided into the following three categories: 1, caused by insufficient blood supply to the feet, generally when the human body oxygen supply is sufficient, it will show a rosy and shiny state, if there is purple, it means that there is a lack of oxygen, especially at the end of the limbs of the feet, so to reduce the local squeeze to increase its oxygen supply. 2, anemia, generally in the state of anemia of people with low hemoglobin, poor oxygen carrying capacity, will appear purple. 3, cold weather, if the weather becomes cold or wear less clothing will cause a slowdown in blood circulation, and then appear purple. 3, cold weather, if the weather becomes cold or wear less clothing, will cause the blood circulation to slow down, and then appear purple condition. All in all, generally purple toenails are related to the local lack of oxygen, in addition to solving the original disease, should be more exercise to increase the local blood circulation.