There is no such thing as “the easiest way to treat black tongue”, the pathological causes of black tongue include extreme heat and yin or cold and yang deficiency, etc., which can be treated with Rhubarb, Huanglian, and Laxative Heart Soup or Four Reversed Soup under the guidance of a doctor. Extreme heat injures the yin: it may be accompanied by dry or cracked tongue, which is related to the prevalence of internal heat, and can be treated with Rhubarb, Yellow Liver and Heart Laxative Soup, which has the effect of diarrhea of heat and elimination of lumps, and can treat abdominal pain, abdominal distension and blackened tongue resulting from the internal prevalence of heat evils. It is forbidden to take it for deficiency of spleen and stomach (spleen and stomach weak and cold), the adverse effect is not clear for the time being, avoid spicy food during the period of taking it. Cold and Yang deficiency: it may be accompanied by wet or slippery tongue coating, related to Yin and Cold internal exuberance, it can be taken Four Reversed Soup, this formula has the efficacy of warming Yang and dispelling Cold (warming Yang Qi and dispelling Cold), it can treat abdominal pain, diarrhea and black tongue coating caused by Yin and Cold internal exuberance. It is contraindicated for Yin deficiency and internal heat constitution, the adverse effect is not clear for the time being, and it is better not to take cold drinks during the period of taking. The above medicines should be used under the guidance of a Chinese medicine practitioner. Please go to the hospital in time to see a traditional Chinese medicine practitioner for diagnosis and treatment in order to avoid adverse effects.