Frequent mouth ulcers and night sweats are often considered to be caused by yin deficiency (liver yin deficiency, kidney yin deficiency, heart yin deficiency, etc.). 1. Liver yin deficiency: often see dizziness, tinnitus, dry eyes, blurred vision, zygomatic, dry mouth and throat, hot hands and feet, baking heat, coercive burning pain in the ribs and hands and feet twitching, etc., the treatment of nourishing yin and nourishing the liver as a mainstay. 2. Kidney Yin insufficiency: often accompanied by soreness of the waist and knees, dizziness, tinnitus, insomnia, hot hands and feet, fever like sitting in a steamer basket, spermatorrhea and premature ejaculation, etc., the treatment should be nourishing yin to lower the main fire. 3. Insufficient heart yin: often see palpitations in the heart, chest tightness, heart pain bouts, insomnia, dreams and easy to wake up, dry mouth and throat, etc., the treatment should be nourishing the heart yin is the main. Mouth ulcers, night sweats alone can not accurately diagnose the condition, it is recommended to consult a doctor in a timely manner, a professional physician four diagnosis and reference (looking, smelling, asking, cutting) before diagnosis and further treatment.