In traditional Chinese medicine (TCM), examination of the tongue plays an important role in diagnosis. The characteristics of the tongue(e.g., color of the tongue body, tongue fur, teeth-marked tongue) provides some clues and prognosis, which are considered a reflection of the body's internal condition. Diabetes mellitus is a metabolic disorder of hyperglycemia, which lead to damage the kidneys, eyes, nerves, blood vessels, and heart. Long standing hyperglycemia can also be associated with buccal alteration. The purpose of this study was to survey on tongue diagnosis and other examinations associated with diabetic mellitus.

Inclusion Criteria:

• diabetic patients(ac sugar>126mg/dl or HbA1c>6.5, twice)
• pre-diabetic patients(100mg/dl \

The investigators recruited the control group , the pre-DM group, and the DM group.