Nails turn yellow may be due to staining caused by the normal phenomenon, this generally do not need to worry too much, may also be due to jaundice, nail fungus, nail malnutrition and other diseases. 1. Physiological factors: often smoke the crowd due to smoke nails can lead to yellow nails; the use of iodine pomade, painted nail polish without primer, nail polish direct contact with the nails and other reasons, can lead to nails are stained and yellow phenomenon, this time do not need to worry too much about it, to improve these habits can be relieved. 2. Jaundice: patients with jaundice can have the symptom of yellowing of nails, in addition, these patients will also have the manifestation of yellow staining of skin and sclera of the whole body, and other symptoms such as nausea and loss of appetite can also occur. 3. ringworm of the nail: ringworm of the nail is a kind of nail lesion caused by the skin fungus violating the nail plate and under the nail, the affected nails in addition to yellowing, but also turbid, thickening, unevenness, shedding and other manifestations. In addition to the above factors, other reasons may also lead to yellow nails, if you exclude the physiological factors, please consult a doctor in a timely manner, under the guidance of the symptomatic treatment, do not take care of yourself, so as not to delay the condition.