Bad breath is mainly caused by indigestion or periodontal disease, it is recommended to consult a doctor for symptomatic treatment; drinking a certain tea can not cure the above symptoms. 1. Indigestion can lead to food accumulation and fermentation in the gastrointestinal tract, which in turn produces belching (hiccups) into the mouth and causes bad breath; must consult the gastroenterology department for symptomatic treatment, such as taking gastric stimulants (domperidone, cisapride, etc.), promoting gastrointestinal peristalsis or digestive medications (probiotics, stomachic tablets, etc.) as prescribed by the doctor to effectively treat bad breath. 2. Periodontal disease is the oral periodontal tissue due to tartar or calculus and other inflammatory substances such as infection and stimulation, and then bleeding gums or oral odor and other symptoms; need to consult a periodontal treatment (such as ultrasonic scaling, periodontal scraping, etc.) to remove the stimulus in order to cure the symptoms of halitosis.