Kidney yin deficiency tongue is mainly manifested as red tongue with little or even no moss, or cracks. Kidney yin deficiency can be caused by prolonged illness, overwork, and poor diet. Kidney yin deficiency mainly manifests as lumbar and knee soreness and weakness (soreness and weakness of the waist and knees), five heart-heat (heat in the hearts of the two hands and the two feet, and self-consciousness of the heart and chest), zygomatic redness, hot flashes, night sweating (sweating abnormally after going to sleep, and sweating stops after waking up), thirst, vertigo, insomnia and dreaming, tinnitus and deafness, spermatorrhea in men, menorrhagia in women, red tongue with little or no moss, cracked, and a fine pulse. Kidney yin deficiency treatment should be based on the principle of nourishing yin and benefiting the kidneys, and can be treated with medicines such as Six-flavored Di Huang Pills, Zuo Gui Pills, Zhi Bai Di Huang Pills, and Da Tonic Yin Pills. If the manifestation of kidney yin deficiency occurs, you should consult a clinician and follow the doctor’s instructions to use medication, do not blindly use medication.