The tongue coating of infants and young children is considered to be related to hygienic habits, and there may also be indigestion. 1. hygiene habits, babies and young children are relatively small, usually after drinking milk if you do not clean up the residue on the tongue, may lead to babies and young children tongue coating thick white. 2. Indigestion, because infants and young children are relatively small, the digestive function is not fully developed, if a one-time eating too much indigestion, may lead to a thick white tongue. 3. Thrush, a fungal infection of the oral cavity, can lead to a thick white tongue, and the oral mucosa usually has a white tofu-like substance attached. Infants and young children with thick white tongue, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to determine the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.