Internal heat due to yin deficiency refers to internal heat caused by the deficiency of yin in the body and the failure of water to control fire. The symptoms are red cheek and red cheeks, thinning of the body, hot flashes and night sweats, irritable heat in the heart, especially at night, dry mouth and dry throat, red tongue with little coating and thin pulse. Treatment is to nourish Yin and clear heat, or to nourish Yin and lower fire. When appearing in specific internal organs, the following manifestations are observed: 1. The main common symptoms of lung yin deficiency are dry cough without phlegm, night sweating, hoarseness, dry throat and sore throat, and dry mouth and thirst. 2. 2, stomach Yin deficiency will also generally appear dry mouth and thirst, do not want to eat no appetite, dry stools and other symptoms. 3. Most people with Spleen Yin deficiency are thin and have dry stools. 4, liver yin deficiency will generally lead to vision loss, blurred vision, because the liver is open to the eyes, often accompanied by mood swings, irritability, liver fire easy to inflame the head and eyes, resulting in dizziness and brain swelling and other symptoms. 5, kidney yin deficiency is a more common yin deficiency condition, easily leading to weakness of the waist and knees, insomnia, forgetfulness, menstrual disorders in women, spermatorrhea in men and other symptoms. The above are the symptoms of Yin deficiency and internal heat, when the specific situation arises, the clinician should identify the evidence to regulate or treat, not blindly treat.