Yellow hair may be caused by malnutrition, and may also have to do with excessive perming and dyeing or iron deficiency anemia and other diseases. 1. Malnutrition: Malnutrition is mainly related to the imbalance or insufficiency of the proportion of nutrients consumed, or digestive dysfunction and other factors. Patients who are chronically deficient in zinc, copper and other trace elements may have yellow hair, and may also suffer from weight loss, slow nail growth and other symptoms. 2. Excessive perming and dyeing: If you often permed and dyed your hair in your daily life, or use alkaline shampoo products frequently, you can make your hair damaged, and thus yellow hair will appear. 3. Iron deficiency anemia: The main causes of iron deficiency anemia are mainly related to insufficient iron intake, impaired iron absorption and utilization, and increased iron demand. Patients will have pale skin, dizziness, dysphagia, difficulty in swallowing, lack of concentration and other symptoms, and some patients will also have dry and yellow hair. There are more reasons for yellow hair, and after excluding the factor of excessive perming and dyeing, it is recommended to go to the hospital for examination to clarify the cause of the disease.