Thirst, dry mouth and frequent urination may be due to heavy sweating, or excessive intake of sugar and salt containing diet resulting in increased osmotic pressure in the body. If the symptoms persist or recur, they may be related to the following diseases: 1. Diabetes: thirst, dry mouth and frequent urination, accompanied by hyperphagia, weight loss and other symptoms are usually considered to be due to diabetes. The excess sugar in the body of diabetic patients is too high and cannot be fully absorbed by the cellular tissues, the excess sugar excreted in the urine will cause an increase in urine osmotic pressure, and the decrease in the amount of water reabsorbed by the renal tubules will result in frequent urination and dry mouth; 2, urolithiasis: acute episodes of thirst, dry mouth and frequent urination are usually associated with urolithiasis episodes, which are mostly due to various causes of renal tubular reabsorption dysfunction, and patients Patients will also show symptoms of irritability, fever, emotional instability; 3, primary aldosteronism: primary aldosteronism episodes are usually associated with increased sodium excretion due to adrenal cortical dysfunction, patients will also show various symptoms such as increased blood pressure, muscle weakness, sensory impairment, diarrhea, etc., in addition to thirst, dry mouth and frequent urination; 4, hypercalcemia: hypercalcemia causes an increase in the concentration of calcium ions in the body It can also cause thirst, dry mouth and frequent urination, accompanied by increased blood pressure, inattention, drowsiness and other symptoms; 5, other: menopausal syndrome, hyperthyroidism, urinary tract infection, mental anxiety and other reasons can also cause symptoms of thirst, dry mouth and frequent urination.