Thirst may be diabetes mellitus, but it may also be caused by physiological factors, or other diseases such as dry syndrome. In addition to thirst, diabetes mellitus may also have hyperphagia, polyuria, weight loss and other manifestations, it is recommended to improve the glucose tolerance, glycated hemoglobin and other tests to clarify the diagnosis. Typical symptoms of diabetes mellitus mainly include thirst, excessive drinking, easy to be hungry, polyphagia, polyuria, weight loss, etc. It can also show non-specific symptoms such as fatigue, drowsiness, mental depression, etc. When there are complications or concomitant diabetes mellitus, the symptoms may be more severe. When suffering from complications or concomitant diseases at the same time, corresponding symptoms can also appear, such as blurred vision, slow wound healing, numbness of hands and feet. Physiological factors such as increased sweating due to exercise or hot weather, improper diet, and decreased water intake can also cause thirst, which is normal. Diseases other than diabetes may also cause thirst. For example, desiccation syndrome, an autoimmune disease characterized by damage to exocrine glands and mainly characterized by dry eyes and dry mouth, may cause thirst. It is recommended to go to the hospital for a thorough examination to confirm the diagnosis.