Thick yellow tongue coating with cracks in the middle may be caused by yin deficiency and internal heat or weakness of the spleen and stomach, which can be regulated by oral administration of proprietary Chinese medicines such as Zhi Bai Di Huang Wan and Xiang Sha Nao Gastric Pill. 1. Yin deficiency and internal heat are usually manifested as symptoms such as “five heart-heat” (heat in the heart of the hands and feet, and self-consciousness of the heart and chest), “night-sweating” (abnormal sweating after going to sleep, but sweating stops after waking up), and “sore throat”, accompanied by symptoms such as yellowish and greasy tongue coating, fissures on the surface of the tongue, and emaciation, etc. The symptoms of this condition should be treated by the principles of nourishing yin and lowering fire (nourishing the yin essence and lowering the fire), as well as nurturing yin and moistening the lungs (nourishing the lungs by replenishing the fluids in the lungs). If treated with proprietary Chinese medicines such as Zhi Bai Di Huang Wan and Bai He Gu Jin Wan, the condition of a yellow tongue with cracks in the center will be relieved. The adverse effects and contraindications of Zhi Bai Di Huang Wan and Bai He Gu Jin Wan are not yet clear. 2. Weakness of the spleen and stomach is usually manifested by symptoms such as loose stools, pale and odorless, fullness in the epigastrium (abdomen), accompanied by yellowish and greasy tongue coating, cracks on the tongue, unfavorable urination, dizziness and easy sweating, etc. This condition should be treated by tonifying qi and strengthening the spleen. This condition should be regulated with the principles of benefiting qi and strengthening the spleen (regulating the qi of the spleen and stomach) and warming the middle and harmonizing the stomach (warming the spleen and stomach, regulating the stomach and internal organs). Symptoms will be relieved if treated with medicines such as Xiangsha Liujun Pill and Xiangsha Stomach Nourishing Pill. Pregnant women should not take Xiangsha Liujun Pill, and the adverse reactions and contraindications of Xiangsha Stomach Nourishing Pill are not yet clear. If you find that your tongue is yellow and thick with cracks in the middle, you should consult a Chinese medicine practitioner to find out the cause of the problem and regulate it under the guidance of your doctor.