Pediatric bitter mouth and red tongue may be caused by not paying attention to oral hygiene, periodontitis, chronic gastritis. 1. Not paying attention to oral hygiene: children’s diet irregular, hot and cold, may lead to the normal flora in the oral cavity imbalance, the symptoms of bitter mouth, while the bacteria stimulate the tongue, the tongue red. 2. Periodontitis: the main manifestation of periodontal inflammation caused by bacterial infection, bacteria in the oral cavity continues to ferment, and the interaction with the normal flora in the oral cavity, affecting the secretion of salivary glands, the symptoms of bitter mouth. The tongue lacks the moisturizing effect of saliva and will also be red. 3. Chronic gastritis: pediatric gastric power is poor, if there is bile reflux, the oral PH value rises, the environment is too alkaline; if there is gastric acid reflux, the oral PH value falls, the environment is too acidic, ultimately leading to an imbalance in the acid-base balance of the oral cavity, will also trigger a bitter mouth and tongue red phenomenon. Children with symptoms of bitter mouth and red tongue, need to go to the hospital as soon as possible, the doctor according to the specific conditions, to develop individualized diagnosis and treatment plan, so as not to delay the condition.