Thigh root black for the local pigmentation caused by the general occurrence in the body fat people, long-term walking friction, or long-term standing, resulting in pigment accumulation in the skin underneath, causing black results. It may also be caused by the increase of melanin in the body due to long-term staying up late. It can be treated by losing weight, changing walking posture and laser treatment. 1. Reduce weight, reduce the inner thigh muscle accumulation, resulting in excessive secretion of sweat glands, always sweating, and poor local ventilation can also lead to increased melanin, so the first to reduce weight. 2. Correct your walking posture, reduce the friction on the inner thighs, wear loose underwear, less tight pants, and do some exercise. 3. If the area is relatively large, the general use of laser treatment, play a role in lightening pigmentation, which is also conducive to improve the expansion of local capillaries, metabolism of melanin. But you need to operate under the guidance of a professional doctor. If the symptoms are not relieved after lifestyle modification and treatment, you should consult a doctor in time to clarify the cause of the disease and carry out treatment under the guidance of a doctor.