Dark tongue coating
Traditional Chinese medicine believes that the darkening of the tongue coating is caused by hot polarized fire. There are also people with gastrointestinal problems that are prone to cold and wet, and the tongue coating will become thick and greasy, starting to be white and gradually turning yellow or black. Patients with dark tongue coating will find that the tongue coating in the middle of the tongue is always black.
The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.