As was described in detail in an earlier part of this series, in Chinese medicine, doctors use the methods of observation, auscultation and olfaction, interrogation, and palpitation to get full and detailed information about the patients and to guide their treatment. These four major methods each have their distinctive function.

The tongue is one of the key examination sites in observation as its shape, color (including that of its coating), and texture reveals the changes of the inner body.