A classical formula for night sweats caused by internal heat from Yin deficiency. It works by nourishing the body's cooling, moistening fluids (Yin) while clearing excess internal fire from all three body regions, and strengthening the body's surface defenses to stop the sweating. Li Dongyuan called it the "sage remedy for night sweats."

This formula addresses a pattern where the body's cooling, moistening Yin substance has become depleted, allowing internal Fire to blaze unchecked. In TCM theory, Yin and Yang exist in dynamic balance. When Kidney Yin becomes insufficient, it can no longer restrain Heart Fire. This uncontrolled Fire is sometimes called "deficiency Fire" (虚火), though the Heat symptoms it produces can be quite intense.

During sleep, the body's protective Qi (which circulates at the surface during the day) moves inward to circulate through the Yin organs. In a person with Yin deficiency, this inward movement of Yang Qi into an already Yin-depleted interior tips the balance further, causing Fire to flare. The Fire forces fluids outward through the skin as sweat, producing the characteristic night sweats (盗汗). Upon waking, the protective Qi returns to the surface and Yin settles, so the sweating stops. The same internal Fire causes a flushed face, dry mouth and lips, irritability, constipation, dark scanty urine, and a red tongue with a rapid pulse.

Because the sweating itself further damages both the Yin fluids and the protective Qi at the body's surface, a vicious cycle develops: Fire drives out fluids as sweat, fluid loss deepens the Yin deficiency, which worsens the Fire, which causes more sweating. The formula breaks this cycle by simultaneously replenishing the depleted Yin, draining the excess Fire from all three Burners (upper, middle, and lower body), and shoring up the weakened surface defense to prevent further fluid loss.