Foundation Knowledge

Yellow Coating

A yellow tongue coating is an important sign of heat. Thick yellow suggests stronger excess heat; thin yellow suggests milder heat.

Foundation

Structured knowledge card

tongue
Definition

A yellow tongue coating usually indicates the presence of heat.

Clinical Meaning

It points toward heat. Thick yellow greasy coating often suggests damp-heat or phlegm-heat, while thin yellow coating may reflect milder heat or stagnation transforming into heat.

Pitfall / Exam Tip

Yellow coating does not automatically mean blazing fire. Its thickness and texture matter.