A thin, dry, deep red tongue is a sign of which condition?

A thin, dry, deep red tongue is indicative of "Heat due to body fluid consumption." In Traditional Chinese Medicine (TCM), the tongue's appearance can provide critical insights into a person's internal conditions.

When body fluids are consumed, whether due to excessive heat, dehydration, or other factors, the tongue reflects these changes. A deep red coloration signifies the presence of heat, while dryness indicates a deficiency of the nourishing fluids in the body. The combination of being thin and dry suggests that the heat is also intense enough to deplete the body's fluids, resulting in the tongue lacking the moist, healthy appearance it would typically have.

This presentation is not consistent with cold conditions or deficiencies associated with yin or yang. Cold in the body might produce a more pallid tongue, while yin deficiency would typically show red with cracks rather than a pronounced deep red hue. Yang deficiency might lead to a pale, swollen tongue as opposed to the thin, dry appearance highlighted in this question. Thus, the signs on the tongue point specifically to a state of heat due to consumption of body fluids.