Nails appear horizontal lines seen in the following cases: 1, nails by trauma resulting in nail plate damage, nail breakage, when the new nails grow and the original nails will appear between a horizontal line; 2, love of beauty of women in order to keep fit, often dieting or picky eaters, resulting in malnutrition in the body, so that the growth of nails need nutrients, can not get enough supply and the formation of horizontal lines; 3, often do the nails of the people, the need to Nail surface of the protective layer removed, and then coated with chemical composition of the nail polish, will make the nails stimulated and appeared horizontal lines; 4, nail fungal infection, psoriasis diffusion damage to the nails, will also appear, there are some heart disease, liver disease patients will also appear this symptom, in the treatment of the need for patients to do the corresponding examination according to the other symptoms, to determine the cause of the disease and then symptomatic treatment.