Dry mouth at night two years after thyroid cancer total excision surgery may have problems such as dehydration, diabetes, dry syndrome, etc., but there should be no relationship with thyroid malignant tumor. 1. dehydration: due to diarrhea or excessive sweating, burns can lead to dehydration, patients show reduced urine, dry mouth, dry skin and mucous membranes and other symptoms, pay attention to drink more water, if necessary, can be rehydrated for treatment. 2. Diabetes: diabetes patients show three more and one less clinical symptoms, mainly for eating more, drinking more, urinating more, but weight loss, patients can appear oral dryness. 3. Dry syndrome: dry syndrome is mainly manifested as an autoimmune disease with the decrease of tears or oral saliva as the main manifestation, and the patients can manifest as dry mouth and obvious decrease of saliva secretion. Two years after the removal of thyroid malignant tumor, pay attention to oral levothyroxine under the guidance of the doctor to supplement the lack of thyroid hormone, pay attention to regular rechecking the level of thyroid hormone, observe the value of thyroglobulin, which will not lead to the problem of oral dryness. For patients with thyroid malignant tumor resection surgery who have oral dryness problems, it is recommended to consult the doctor in time, improve the examination, clarify the cause and diagnosis, and standardize the treatment under the guidance of the doctor.