The causes of white horizontal lines on fingernails in children include the following two main conditions. The first is due to nutritional anemia, children’s growth and development is relatively rapid, if not pay attention to iron supplements, in this case will appear iron deficiency anemia, iron deficiency anemia will lead to a decline in hemoglobin, some children will have white horizontal finger nails performance. For this condition, children can be given iron supplements, such as ferrous succinate, and usually eat more beef and duck blood. The second is due to the lack of trace elements, if the child usually partiality, picky eating, and thus not able to balanced intake of nutrition, so it is easy to appear zinc deficiency, calcium deficiency, etc., will also appear finger nails with white horizontal lines performance. In this case, it is important to take the child for a blood test for trace elements in a timely manner.