The patient is asked to sit down or lie in supination, exposed to the light source. The tongue is protruded naturally and the tip of the tongue is kept slightly downwards. The mouth is opened wide to make the tongue exposed fully.

The sequence of inspection of the tongue begins from the tip of the tongue, then the middle and margin of the tongue, and finally the root of the tongue. The inspection begins with the tongue body first and then moves to the tongue fur. The inspection should be complete and quick.
      
In the inspection of tongue, trials should be made to exclude various false manifestations, such as "dyed tongue fur" due to light, diet and drugs. Inspection of the tongue mainly includes the examination of the tongue proper and the tongue fur.
 
The body of the tongue is composed of muscles and vessels. In the ancient times, some people believed that the surface of the tongue corresponded to the viscera. That is to say the tip of the tongue reflects the pathological changes of the heart and lung, the center of the tongue reflects the pathological changes of the spleen and stomach, the root of the tongue reflects the pathological changes of the kidney and the margins of the tongue reflect the pathological changes of the liver and gallbladder. Such an idea about the correspondence of the tongue to the viscera is clinically practical. However, the analysis should be comprehensive and based on the changes of the tongue body and tongue fur.

Inspection of the body of the tongue includes the color, shape, texture and movement of the tongue, which reflect the conditions of the viscera, qi and blood. The tongue fur or coating refers to the lichen-like material formed on the surface of the tongue. Inspection of the color of the tongue and fur can reveal the conditions and nature of pathogenic factors as well as the interaction between healthy qi and pathogenic factors.