Is Thick, Greasy Tongue Coating "Fire"?

In traditional Chinese medicine, thick, greasy tongue coating is most commonly not due to "fire," but rather "stagnation of stomach qi"—that is, a decline in the entire digestive system's function, typically seen in those who consume excessive amounts of fish, meat, and sweet, rich foods. How can one determine if there is actual "fire"? According to basic principles of traditional Chinese diagnosis, if thick, greasy tongue coating is accompanied by symptoms such as bitter mouth, sticky mouth, bad breath, mouth sores, thirst, constipation in the lower jiao, or yellow, foul-smelling urine, or even anal burning and abscesses, then it is considered "fire." Without these symptoms, it is merely "food accumulation inside." Patients need only take some heat-clearing medicines to help the tongue coating recede.
Another situation commonly seen in children or elderly people with weak spleen and stomach, or those recovering from long-term or serious illness. Due to qi and blood deficiency and weakened digestive function, they cannot properly digest, absorb, or excrete, leading to thick, greasy tongue coating. Traditional Chinese medicine calls this "deficiency at the root, excess at the surface." If this is classified as "fire," it would severely damage the already weak spleen and stomach function and the entire body under the harsh effects of cold, bitter medicines. In such cases, patients are best advised to consult a specialist doctor for medication.