Nails that are yellow in color are related to food factors, long-term smoking and liver and gallbladder diseases. 1. Food factors: some patients may be due to long-term intake of large amounts of pumpkin, citrus, carrots, oranges and other foods, may produce hypercarotenemia, and then there will be nail color yellow and skin yellowing symptoms. 2. Long-term smoking: For people who have been smoking for a long time, the smoke may cause yellowing of the nails. 3. Liver and gallbladder diseases: for example, patients with jaundice caused by cholestasis, due to bilirubin metabolism disorders, resulting in an increase in the concentration of bilirubin in the serum, the skin, mucous membranes, and nails yellowing symptoms. There may be other reasons for yellow nails, so it is necessary to cooperate with the doctor to improve the examination, and then treatment and therapy.