White and thick tongue coating in the middle and back of the tongue is related to weakness of the spleen and stomach, stagnation, and phlegm (a pathological product of impaired metabolism of water and fluid). 1. Weakness of the spleen and stomach: Weakness of the spleen and stomach is related to dietary intemperance, overwork, and old age. Typical symptoms of patients include diarrhea, yellowish color, fatigue (lack of energy), thinness and weakness. There is no strength), thin and weak, etc. Some patients may show that the middle and back of the tongue is white and thick. 2. Stagnation: stagnation and vegetative spleen deficiency, post-disease disorders, breastfeeding, etc., patients are commonly manifested with decreased appetite, gastric and abdominal distension, belching (belching), stool abnormalities, etc., can also be manifested as a thick tongue coating in the middle and back of the tongue. 3. Phlegm drink: phlegm drink is formed when water and fluid in the body cannot be transported and gathered in certain parts of the body, which is mainly related to cold and dampness, improper diet, and physical weakness. Common manifestations include swelling of the limbs, fullness in the chest and ribs, and fullness under the heart, which can be manifested as white and thick tongue coating in the middle and back of the tongue. It is recommended to consult a doctor and follow the doctor’s instructions to avoid delaying the condition.