Kidney yin deficiency, a type of kidney deficiency, refers to the evidence of insufficient yin fluid in the kidneys. Kidney yin deficiency, also known as kidney water deficiency or true yin deficiency, is usually caused by prolonged illness that injures the kidneys, congenital endowment deficiency (poor innate constitution and functioning), excessive intercourse, excessive consumption of warm and dry products that injure the yin, acute febrile illnesses, and internal injuries of emotions and feelings. Patients with kidney yin deficiency usually show dizziness, tinnitus, pain in the waist and knees, insomnia, night sweating (abnormal sweating after going to sleep and stopping sweating after waking up), dry throat, zygomatic redness (reddish color of cheeks and zygomatic bones), loose teeth, loss of hair, emaciation, short and yellowish urination, dryness of stools, and a red tongue with little fluids. Patients with kidney yin deficiency can be treated by taking, for example, Liu Wei Di Huang Wan. Six-flavored Dihuang Pill is composed of ripened rhubarb, cornelian cherry and peony bark, which has the effect of nourishing yin and tonifying the kidneys, and is commonly used in the treatment of dizziness and tinnitus, lumbar and knee soreness and weakness (a feeling of soreness and weakness of the lumbar and knee), bone vapor and dampness and heat (a burst of heat, and feeling that the heat is penetrating from the inside of the bone to the outside), and spermatorrhea and night sweating, etc. It is recommended that patients should take timely treatment. It is recommended that patients in need of treatment should seek timely medical attention and be treated under the guidance of a doctor.