The tongue is an important organ in the oral cavity that has many functions such as participating in mastication and speech, assisting in swallowing and expression, and perceiving taste. The tongue is composed mainly of muscles with a mucous membrane on its surface. Usually, the side of the tongue where the mucosa is observed is called the dorsum of the tongue, while the side attached to the bottom of the mouth is the abdomen of the tongue. There are many lingual papillae on the mucosal surface of the first third of the dorsum of the tongue, which can be divided into four types, including filiform papillae, fungiform papillae, contoured papillae and lobed papillae, depending on their shape and size and other characteristics. The taste buds for sensation of taste are mainly located on the dorsal mycotic papillae and the contour papillae of the tongue. The tongue, which is closely related to our life, is susceptible to many diseases. The more common one is atrophic linguitis, which has many causes, mainly due to anemia, niacin deficiency, dry syndrome or Candida infection. In elderly patients, atrophic linguitis caused by Candida infection is the most common. The main manifestation is atrophy of the lingual papillae on the dorsum of the tongue, a smooth, reddish tongue with no tongue coating, and in severe cases, a dry and thin tongue due to thinning of the tongue muscles. This is also known as smooth tongue or mirror tongue. It is important to find the cause of the problem and treat it accordingly. Map tongue is also more common. It is a non-infectious inflammatory condition. Atrophy and recovery of the tongue papillae occurs simultaneously on the dorsum of the tongue. It appears as an irregular single or multiple annular erythema that quickly expands or fuses to resemble a map. The lesion is characterized by atrophy of the lingual papillae in the center of the lesion and mucosal congestion, showing a smooth, exfoliative erythema surrounded by edematous lingual papillae with yellowish-white, slightly elevated edges that articulate with each other in a curved shape. Because the damage is atypical and the lesion is displaced, it is also called wandering tongue. There are many causes of map tongue, which may be related to genetics, poor digestion, micronutrient deficiency, emotional changes, etc. Inflammatory conditions such as dental caries and viral infections may also be triggering factors. Guttate tongue is easily associated with map tongue. The main manifestation is the appearance of fissures on the dorsal mucosa of the tongue in different directions. The incidence of the disease tends to increase with age. There is no uniform understanding of the etiology of the disease. Currently, it is thought to be related to geography, vitamin deficiency, allergic reactions, viral infections, plant nervous disorders, etc. Map tongue and grooved tongue generally do not require treatment, if there is pain when eating irritating food, available chlorhexidine and other mouthwash containing Shu. When gargling, the tip of the tongue can be placed against the inner side of the lower front teeth, the back of the tongue arch, so that the tongue body open, so as to facilitate the cleaning and anti-inflammatory deep cleft groove. Poor oral hygiene, excessive smoking, long-term application of antibiotics or rinses can cause “hairy tongue”, which is caused by over-elongation of the lingual papillae on the back of the tongue and staining with pigment. The treatment of this disease is simple: remove the cause, pay attention to oral hygiene, adjust the application of antibiotics, quit smoking, avoid taking coloring food such as coffee, Chinese medicine, chocolate, etc.; scrub the hairy tongue area with a toothbrush to mechanically remove Candida and keratinized elongated papillae. The back of the tongue can return to normal after two or three weeks. Middle-aged and elderly people sometimes feel uncomfortable at the root of the tongue and fear that they have cancer, so they often take a mirror to check the back of the tongue by themselves. This is what we often call “cancer fear”. It is generally recommended not to check the back of the tongue by yourself, and the symptoms will gradually and naturally be relieved when the tongue body gets sufficient rest. If you are still unsure, you can go to the hospital. The tongue is considered to be the “window to disease”. Not only is the tongue the site of many oral mucosal diseases, but many systemic diseases have typical manifestations on the tongue mucosa. Examples include recurrent mouth ulcers, lichen planus, syphilis, etc. Particular attention should be paid to: the edge of the tongue, the abdomen of the tongue and the floor of the mouth. In case of long-standing ulcers, it is important to visit the hospital to prevent the development of lesions. We need to pay attention to the health of the tongue. Normally, we should pay attention to maintain oral hygiene, remove root and crown remnants in time, do not smoke, reduce the consumption of too spicy and hot food, and avoid strong physical and chemical stimulation. When the tongue is healthy, we can eat better and communicate well with others.