The tongue’s coating is also examined. A thin white layer is considered normal, but its absence may signify dehydration. A dry yellow tongue indicates body heat, with a more intense color indicating higher body temperature, potentially signaling inflammation, bacterial buildup, or other imbalances. A gray or blackish tongue may indicate stagnation in the flow of energy, blood, and fluids.

The texture of the tongue’s surface can reveal health issues. Bumps or cracks may indicate various problems, with the location and appearance of these abnormalities providing diagnostic clues. For instance, a bump on the front of the tongue may signal infection or an allergic reaction, while deep cracks in the center may suggest digestive system vulnerabilities. The “geographic tongue,” characterized by white patches, may indicate stomach heat, possibly linked to esophageal reflux. Protrusions on the outer edge of the tongue may indicate fluid retention in the body.