Anyone who has seen a TCM doctor has done the “tongue out” exercise. The reason why doctors look at the tongue is that the tongue is connected to the meridians of the liver, heart, spleen, lungs and kidneys, and if there is any disease in the internal organs, it can be reflected visually on the tongue. Therefore, to a certain extent, changes in the tongue are a barometer of the health status of the human body. A normal tongue can be summarized in six words: light red, thin tongue and white moss. Specifically, the tongue is light red, moist, medium-sized, soft and flexible, and evenly coated with a thin, white and moist tongue. Chinese medicine divides the tongue into tip, middle, root and side of the tongue. The tip of the tongue belongs to the heart and lungs, the middle of the tongue belongs to the spleen and stomach, the root of the tongue belongs to the kidney and large intestine, and the sides of the tongue belong to the liver and gallbladder. A healthy person’s tongue is light red and moist, indicating the harmonization of Qi and blood in the body. A pale white tongue, i.e. a red tongue with less white color, is mostly seen in Yang deficiency evidence, Qi and Blood deficiency evidence, such as women with anemia. If the tongue is bright red, it is mostly seen in heat evidence. If the red tongue is accompanied by irritability, dry throat, cold drinks and mouth ulcers, it is often seen in people with hyperactive heart fire. If the tongue is blue, it usually indicates that yin-cold is more prevalent, or there is evidence of stasis, dysmenorrhea, menstrual disorders in women, certain patients with congenital heart disease or drug or food poisoning will appear. If the tongue is hard and trembling, it indicates internal movement of liver wind and wind-phlegm obstruction, which is mostly seen in patients with hypertension or indicates the risk of stroke. If the tongue is fat and there are teeth marks on the edge of the tongue, it indicates a relative deficiency in the transport and transformation function of the spleen and stomach, mostly seen in a body with spleen deficiency and heavy dampness, so you can add some foods with the ability to strengthen the spleen and transform dampness, such as yam, atractylodes, white lentils, etc. Some people have moss on their tongues in some places and no moss in others, which is called “map tongue” in Chinese medicine, if there is no discomfort, it is a physiological phenomenon and does not require treatment. If a person has long term stomach problems or other chronic diseases, it is mostly Yin deficiency. The tongue moss is produced by the stomach qi. Observe the color, moistness and thickness of the tongue moss. A thickened, moist and greasy tongue moss is caused by damp evil caught in the stomach qi, or there is phlegm, dampness, water, drinking and food accumulation in the body, suggesting that the patient may have digestive system or respiratory system diseases. A change from thick to thin tongue moss and a new thin white moss on the tongue indicates a change for the better; a change from thin to thick tongue moss indicates a gradual increase of evil qi or a worsening of the condition due to superficial evil entering the body. The yellow color of the tongue moss indicates the presence of internal evidence and heat evidence in the body. Black or gray moss is more common in people who have been ill for a long time or are seriously ill. You can also observe the thickness and color of the blood vessels and meridians at the base of the tongue, which are normally moderately thick and thin, with a greenish purple color. If the veins become thicker and the color is bruised purple, the condition of patients with cardiovascular disease may be aggravated. It should be reminded that although the tongue image can reflect the changes in the internal organs and meridians of the human body, it should not be used as a reference for diagnosis of disease based on the tongue alone. It should also be used in conjunction with the whole body to make a correct diagnosis. Therefore, it is important to see a doctor in a timely manner when you are not feeling well.