The tongue is dark with a white coating. There are generally three reasons for this tongue sign: food accumulation, liver stagnation with blood stasis, and internal retention of dampness.
Food accumulation refers to irregular eating habits or the spleen and stomach failing to receive, digest, and transport food properly, causing food to stagnate in the gastrointestinal tract after eating. This can lead to bloating and pain, belching sour gas, vomiting sour and decayed food, and other symptoms, resulting in a purple-dark tongue with a white greasy coating.
For food accumulation, medications like Baohe Pill and Citrus Peel Rhubarb Pill can be taken to aid digestion and relieve symptoms.
Liver stagnation with blood stasis is due to liver qi stagnation and impeded qi and blood flow, which manifests as a purple-dark tongue with a white greasy coating.
