Yellowish nails, in Chinese medicine, is thought to be caused by dampness and heat, commonly found in hypothyroidism, nephrotic syndrome. In Western medicine, yellowish nails are mostly related to vitamin E deficiency. If all the nails turn yellow, you need to receive treatment because it is a sign of systemic weakness. If you want to improve the phenomenon of yellowing nails, you can try to take a spoonful of salt with lemon juice and mix, and then use a toothbrush to apply on the nails, brush carefully, once a day, for three days, you will find that the yellowing of the nails have a significant discoloration. Because lemon juice has a whitening effect, salt can be rubbed on the surface of the nail, will also whiten and fade. Yellow nails may also be due to calcium deficiency and other causes, so daily attention should be paid to more calcium supplements, do not favor food, you can eat fat, carbohydrates and other foods.