Dark yellow and black skin may be caused by lack of vitamins, skin dehydration, liver lesions, endocrine disorders, etc. It is recommended that timely consultation and treatment. 1. Lack of vitamins: dark yellow skin may be caused by lack of vitamins, lack of vitamins, will lead to aging cells can not be shed in time, pigmentation, resulting in dark yellow skin, if the picky eaters or partiality, resulting in nutritional deficiencies, there will also be dark yellow skin. 2. Skin dehydration: Skin dehydration may also lead to dark yellow, environmental factors lead to dry skin caused by excessive dehydration of the skin, dry skin, the appearance of the skin looks yellowish black, timely hydration, keep the skin moisturized. 3. Liver lesions: dark yellow and black skin may be caused by liver disease, such as liver disease, the body can not metabolize toxins in a timely manner, so that the toxins can not be effectively discharged for a long period of time, accumulating in the body, resulting in dark yellow and black skin. 4. Endocrine disorders: dark yellow and black skin may be due to bad habits, such as staying up late, smoking, alcoholism, etc., resulting in endocrine disorders, causing hormone levels to change, the body’s pigment cells are active in the case of dark yellow and black skin. There are many other reasons for dark yellow skin, it is recommended to go to the hospital in time to avoid blindly using drugs.