Yellow urine and dry mouth are mostly caused by a decrease in peripheral circulatory blood volume due to low water intake or heavy sweating. In general, the phenomenon of yellow urine and dry mouth is mostly considered to be due to less water intake, or in a hot environment and strenuous exercise, etc. leading to a large amount of water evaporation through sweat, resulting in a decrease in the peripheral circulating blood volume, which in turn causes a decrease in the glomerular filtration rate, leading to a decrease in the amount of urine, the concentration of urine, and the emergence of the symptom of yellow urine. At the same time, the decrease in circulating blood volume will lead to increased osmotic pressure, stimulate the osmotic pressure receptors in the hypothalamus, and the excitement is transmitted to the brain to cause thirst. The appearance of yellow urine and dry mouth can be appropriate to drink more water, the symptoms can generally be relieved. If there are other symptoms at the same time, it is recommended to go to the hospital for examination to clarify the cause of the disease.