The causes of blue tongue may include physiological factors such as individual differences and improper diet, as well as pathological factors such as poor blood circulation and hemangioma, etc. Patients should be adjusted according to different causes. 1. Physiological factors: (1) Individual differences: some people have more dense and abundant blood vessels and thinner mucosal tissues, so they will show the phenomenon of blue tongue. This situation generally does not need to be adjusted, close observation can be. (2) Improper diet: due to eating some green or greenish-colored food, after chewing, it will show the illusion of a green tongue. In this case, avoid eating this kind of food and observe if the situation improves. If the situation improves, then generally do not need to be adjusted, reduce the consumption of such foods can be. 2. Pathological factors: (1) Poor blood circulation: Due to poor blood circulation, the blood viscosity is relatively high, so it will be manifested as the symptom of blue tongue. Patients can eat some foods that replenish qi and blood, such as brown sugar and red dates, and avoid eating spicy, irritating and greasy foods. (2) Hemangioma: If there is hemangioma on the tongue, it will cause local skin congestion, and the deeper part of the tongue will appear blue and bulging. Patients can follow the doctor’s instructions to apply drugs such as bleomycin, pingyangmycin, glucocorticoids and other treatments, and at the same time, avoid scratching and squeezing the hemangioma, and undergo surgical treatment if necessary. If the blue tongue can not be relieved after conditioning, it should be diagnosed and treated in time to avoid delaying the condition.