White tongue coating may be caused by feeling cold evil, dampness or cold evil in the body. 1. Feeling cold evil: If the patient feels the external evil, such as wind evil or cold evil, after the external evil has not spread inside, the tongue coating is often thin and white. In the early stage of wind-cold flu, there is thin white moss with symptoms such as fear of cold, nasal congestion and runny nose. 2. Dampness or cold in the body: If the patient’s tongue is pale white and moist, it is usually a cold-dampness or internal cold syndrome, which is usually accompanied by symptoms such as coldness around the body and limbs. They usually like to eat warm food and are prone to diarrhea when they are cold. There are many other reasons for white tongue coating, and patients are advised to actively seek medical attention, and if they have any uncomfortable symptoms, it is recommended that they be treated under the guidance of a professional doctor.