Sweating on the forehead may be related to physiological reasons, or it may be caused by vitamin D deficiency, hyperthyroidism and other pathological reasons. 1. Physiological reasons: may be related to the environment, if the long time to stay in a higher temperature environment, it is easy to cause forehead sweating. In addition, when encountering certain stressful events, resulting in emotional over-excitement or excitement, or long hours of heavy manual labor overwork, may cause forehead sweating easily. 2. Pathologic causes: (1) Vitamin D deficiency: common in infants and young children, usually caused by insufficient intake of vitamin D or long-term lack of sun exposure. Patients can appear irritable, irritable, night crying, excessive sweating and other symptoms, can appear forehead sweating easily and so on, and can cause rickets in severe cases. (2) hyperthyroidism: due to the patient’s overactive thyroid function, resulting in increased secretion of thyroid hormones, resulting in hypermetabolism of the patient’s body, resulting in increased neural excitability, which may cause forehead sweating easily, and may be accompanied by irritability, hyperphagia, and other manifestations. It is recommended that patients who sweat easily on the forehead should go to the hospital in a timely manner after eliminating the physiological causes, so that they can be diagnosed clearly and treated under the guidance of the doctor.