Bad breath with yellow tongue coating may be caused by stomach fire, may also be caused by liver fire in the stomach, the specific need for professional Chinese medicine combined with the patient’s symptoms and tongue and pulse signs for identification. 1. If stagnation in the stomach, stagnation for a long time, resulting in fire, resulting in turbid gas instead of descending to rise, it will cause the symptoms of white thick tongue, bad breath, may also be accompanied by hiccups (hiccups), stomach pain, easy to hunger and other manifestations. When stomach fire is strong, the tongue is red, the tongue coating is yellow, and the pulse is mainly slippery. 2. When Liver Fire is exuberant, it will deplete the essence, resulting in a whitish and dry tongue, inflammation of Liver Fire, dry mouth, bitter mouth, and even bad breath, and may be accompanied by symptoms such as redness of the face, redness of the eyes, dizziness, ringing in the ears, and distension and pain in the chest and ribs. When liver fire is exuberant, the tongue is red, the tongue coating is yellow and greasy, and the pulse is mainly stringy. Therefore, the occurrence of bad breath and yellow tongue coating, the need for professional doctors of traditional Chinese medicine combined with the patient’s symptoms and tongue and pulse for diagnosis and treatment, do not recommend their own subjective judgment, so as not to delay the condition.