1. Brown longitudinal stripes or cracks appear on the nail surface, extending from the fingertips to the nail roots, suggesting inflammatory lesions in the intestine or suggesting vitamin deficiency and iron deficiency. Partial whitening of nails indicates zinc deficiency. Ordinary whitish indicates anemia. Brown stripes appear on nails, which is a signal of liver disease. But it is worth noting that this tan stripe should appear on ten fingernails at the same time, which is liver disease; Isolated appearance cannot be used as a basis for diagnosis. There is a straight line on the nail, which is a proof of overwork and overuse of the brain. 3. Fingernails are closely related to health. Healthy nails are soft, shiny and transparent pink. The main component of nails is a kind of protein called keratin, so if you want to have healthy nails, you must ensure that you get enough high-quality protein. When the body is sick, the nails will also be abnormal. For example, the appearance of stripes or wrinkles on nails is a signal that health is red. Longitudinal grooves appear on nails, indicating abnormal circulatory system; On the contrary, if there is a lateral groove on the nail, it means that it is a trace left by measles, or a sign of fever, or pregnancy, zinc deficiency in the body and so on. Generally speaking, the most common symptom is nail cracking, which is not simply the result of not paying attention to protecting nails. The root cause may be malnutrition or anemia. If the nails turn dark brown or uneven for no reason, it is probably because there is a fungus similar to mold on the nails. In addition, sometimes the tips of nails become very thin, like white eggshells. The reason for this phenomenon is poor nutritional status or abnormal nervous system. If the nail becomes thinner and thinner, the whole nail or nail tip sinks like a spoon. Besides trauma, chronic anemia or liver disease may also be the root cause.