The normal color of human finger (toe) nails is light red and lustrous, but if the human physiological function is disturbed, resulting in the occurrence of disease or malnutrition, trauma, infection, poisoning, application of drugs or environmental and life changes, can cause finger (toe) nail color change. Differential diagnosis of finger (toe) nail color change: 1, a person suffering from chronic diseases, long-term emotional depression, smoking, or finger contact with chemical stains such as copy paper, hair dye can make the nail discoloration or staining. If the nails are stained deeply, it is better to wait until the new nails grow out. If you want to get rid of the surface staining in time, you can use a slice of lemon to rub your fingertips repeatedly, and then clean and dry them. 2, If you lack protein or iron for a long time, it usually causes spoon like or flat nails, which can be corrected by improving your diet. It is said that wearing artificial nails can help nails store moisture and become soft, causing nails to bend upwards, this problem should increase nutrition as appropriate, remove the artificial nails worn. 3. Lack of nail luster usually reveals a possible lack of protein, lack of vitamins A and B or reveals a mineral deficiency. This can be addressed by improving your daily diet and taking a daily multivitamin supplement. Adding vitamin B6 and 15 grams of zinc is sufficient. If the nails are white, it may indicate a liver disorder, which can be treated with the help of an internist. 4. When the nails are pale, this may be a sign of a lack of zinc and vitamin B6, or may be caused by anemia. If the symptoms of pale nails persist even after improving the nutritional status of the diet, it is time to seek medical advice to identify the cause. 5. Some patients have cracked nails, which indicate a lack of calcium, protein, and sulfur in the body.