Special thirst is clinically common in the following areas: 1. diabetes mellitus, patients will appear dry mouth, irritable thirst, excessive drinking, polyuria, wasting, monitoring fingertip blood glucose or intravenous blood glucose is significantly elevated, can meet the diagnostic criteria of diabetes mellitus. 2. dry syndrome, this is an autoimmune disease, will appear dry eyes, dry mouth, serious cases can appear heart, lung and other system complications. 3. uremia It is also an endocrine disorder, with irritable thirst, dry mouth, excessive drinking, polyuria and low specific gravity urine, and the amount of water drunk can reach more than 4000ml per day.