A five-year-old child with a white thick tongue may be caused by indigestion, poor oral hygiene, chronic gastritis and other reasons. 1. indigestion: children are young, weak digestive function, and do not pay attention to dietary control, eat too much at a time, especially meat, will cause children indigestion, tongue thick and greasy. 2. Oral cleaning is not in place: white tongue is mainly because the oral cavity itself is poor cleaning ability, need to develop good eating habits, diet should be regular meals, rinse after meals, brush your teeth on time. 3. Chronic gastritis: chronic gastritis is characterized by indigestion and white tongue coating. Chronic gastritis is due to indigestion and caused by the bitter taste in the mouth, the tongue coating is thick and white, which is related to the usual diet, work and rest, do not eat on time. Five-year-old children with symptoms of white thick tongue, should seek medical treatment, to avoid self-judgment, the wrong condition.