Have you been struggling recently because your mouth feels unusually dry and your tongue parched? No matter how much water you drink, relief is brief, and a burning throat may have even disturbed your sleep at night. Many patients visit clinics with worry, wondering why they are so thirsty and whether it might indicate a serious illness. The Donguibogam does not view this thirst and xerostomia simply as a lack of water.
Within our bodies is a vital substance called body fluids. Much like dew in a forest or a stream enriching the soil, body fluids are formed when nutrients absorbed from food transform to moisten the entire body. Every sensory opening—including the eyes, nose, and mouth—as well as the skin, internal organs, and bones depend on body fluids to function properly. The Donguibogam explains that body fluids are generated in the spleen and stomach, ascend to the lung to circulate and moisten the whole body, and descend to the kidney for storage. This resembles a water treatment facility filtering clean water to distribute throughout a home, which is later collected in a reservoir.
When body fluids cannot be sufficiently produced or are consumed too quickly, difficulties follow. Just as soil cracks during a summer drought, when body fluids dry up, a parched mouth and a burning throat appear as thirst and xerostomia. The Donguibogam notes that when internal fire and heat become excessive, or when the energy of the five viscera and six bowels weakens into yin deficiency, body fluids evaporate rapidly or fail to form. This corresponds to the common expression of having too much heat in the body. When heat is excessive, fluids boil away, and when the body's constitution weakens, it cannot retain fluids, allowing them to leak away. When body fluids become depleted, the issue extends beyond thirst to systemic discomforts such as rough skin, dry eyes, constipation, and restless sleep. This illustrates the importance of fluid balance in the body.
