Yellow tongue coating may be related to the food eaten, poor oral hygiene, gastrointestinal tract dysfunction, chronic hepatitis and other factors. 1. Food: you may have eaten oranges, mangoes, orange juice and other foods with yellow pigment, pigment attached to the tongue will have a yellow phenomenon. 2. Poor oral hygiene: If you don’t have the habit of brushing your teeth or brush your teeth carefully, there will be more food residues and bacteria in your mouth, which will lead to yellow tongue coating and accompanied by bad taste in your mouth. 3. Gastrointestinal tract dysfunction: For example, patients with colitis, habitual constipation, dyspepsia, etc. will have gastrointestinal tract dysfunction, which will be manifested as yellow tongue coating, and usually have anorexia, nausea, vomiting and other symptoms. 4. Chronic hepatitis: due to the impact of chronic hepatitis, liver metabolism will have certain obstacles, there may also be some patients will appear yellow tongue phenomenon. It is recommended that patients exclude food and other causes, timely to the hospital for examination to clarify the cause, and follow the doctor’s instructions for treatment.