Bitterness in the mouth refers to a bitter taste in the mouth, which is one of the manifestations of abnormal taste. There are many causes of bitterness in the mouth, including infections, fever, chronic diseases such as esophagitis, bile reflux gastritis, tumors, and especially gallbladder diseases; other people such as fatigue, lack of sleep, excessive smoking, alcoholism, snoring, sleeping with mouth open, and inflammation of the mouth are also prone to bitterness. In addition, excessive work and study pressure, mental tension, irritability, anxiety, fear and insomnia may also cause bitterness in the mouth. The key points of differentiation between actual heat and deficiency cold: 1. Bitter mouth: bitter and dry mouth, thirsty for water, drink it quickly; or bitter mouth, spicy sensation on the tongue; or bitter mouth, with foul smell in the mouth. The moss is yellow and dry or yellow greasy, and the tongue is red or red-red. 2.Mouth bitterness in the main deficiency cold: bitter and light mouth, thirsty but not thinking of drinking, not much drinking; or bitter and salty mouth with saliva; or mouth with clear water, the moss is mostly white and smooth, or white and greasy, or white and greasy hood gray-black, the tongue is light or light white and fat and tender, with many tooth marks on the side. The symptoms include bitterness in the mouth and pain in the throat, deafness and swelling in the ears, yellow and dry moss or yellowish greasy moss, red or red-red tongue. Yin dampness, Yin itching, blood in urine, or even tendon impotence and Yin pain. Treatment can be done by adding and subtracting gentian and liver diarrhea soup. Deficiency cold evidence: 1. Deficiency cold of the spleen and stomach: clinically, mouth bitterness caused by deficiency cold of the spleen and stomach, more bitter mouth and light, thirst without thinking of drinking; or mouth bitter and salty and salivary; or mouth more clear water. The tongue coating is mostly white and smooth, or white and greasy, or white and greasy hooded gray-black, with a light or light white and fat tongue and many teeth marks on the side. The main clinical evidence is bitterness of the mouth, soreness and weakness of the waist and knees. The concurrent evidence is mostly due to liver yin deficiency and liver qi stagnation causing pain in the ribs; or liver and kidney deficiency causing soreness and weakness in the waist and knees, dizziness and dizziness; or even due to yin deficiency causing internal heat causing thirst and insomnia, red tongue with thin coating and fine pulse. It can be treated with Zhi Bai Di Huang Wan plus or minus a prescription for treating mouth bitterness: Sang Dan Drain Bile Tang: Composition: Mulberry Leaf 9g, Dan Pi 9g, Gentian Herb 3-9g, Raw Oyster 30g, Raw Licorice 9g. Gentiana is bitter-cold, sinking yin downward, clearing and lowering bile fire; Mouton is salty-cold, nourishing water and connoting wood, converging bile fire. Raw licorice is mild and sweet in nature, clearing heat and detoxifying, harmonizing all medicines. This formula has good therapeutic effect on mouth bitterness caused by overflowing of bile, and it is suitable for all types of mouth bitterness treatment by combining with dialectical evidence, which is a more ideal basic formula for specific diseases. Commonly used Chinese patent medicines for treating mouth bitterness: 1.Gentian diarrhea liver pill; 2.Danggui Longxue capsule; 3.Xiao Chaihu granule; 4.Danjia Yiyao capsule; 5.Ri Zhong pill; 6.Zhi Bai Dihuang pill.