There are usually two major causes of dry mouth immediately after just drinking water. From the perspective of Chinese medicine identification, it belongs to deficiency evidence, usually triggered by kidney yin deficiency and kidney yang deficiency. From the perspective of Western medicine, dry mouth immediately after just drinking water is usually caused by three major endocrine diseases: 1, the most common disease for diabetes, when patients suffer from diabetes, often appear thirsty, drinking, polyuria, just after drinking water immediately have dry mouth and tongue, mainly triggered by increased blood sugar in the body. 2, just after drinking water dry mouth is because suffering from metabolic diseases, such as hyperthyroidism, triggering dry mouth. 3, also common in endocrine metabolic diseases, such as adrenal pheochromocytoma, will also cause dehydration, dry mouth, etc..