Kidney water, usually referred to as Kidney yin, is the part of Kidney qi that has cooling, moisturizing, tranquilizing and inhibiting effects. Kidney yin is relative to kidney yang, and both are transformed by the essence in the kidneys. Kidney qi is produced by kidney essence and has the function of promoting and regulating human growth and development, enabling one to have the ability to reproduce, and promoting and regulating the metabolism of fluids in the whole body. Kidney yin is the part of kidney qi that moisturizes and inhibits. If kidney yin is insufficient and cannot control yang, and there are hot flashes (a burst of heat), night sweating (abnormal sweating after going to sleep and stopping after waking up), heartburn and heat (heat in the heart of the hands and feet, and self-consciousness of the heart and chest), hypersexuality, spermatorrhea, lumbar and knee soreness and weakness (a feeling of soreness and weakness of the lumbar and knee), a red tongue with little moss, and a thin and countless pulse (a pulse that becomes narrower and finer, and at an accelerated rate), then the treatment should be to nourish the kidney yin. For more knowledge about TCM theory, it is recommended to read the specialized textbooks or consult a specialized TCM doctor, and not to blindly identify the symptoms on your own in real life, in order to avoid adverse consequences.