In the research of Chinese medicine constitution classification

tongue manifestation is the easiest to master and is the easiest to objectify. In present constitution classification

tongue manifestation is most from the clinical examination or summary of ancient and modern literature by researchers. There is a gap between results from a large sample survey of modern constitution and tongue manifestation described in common constitution diagnostic criteria. The authors think that Chinese medicine visceral manifestations

Qi-blood theories

and modern image processing and analysis technology should be combined. The intrinsic association regulation between tongue manifestation characteristics and constitution type should be explored. Regional Chinese medicine constitution tongue manifestation database of different ages should be constructed to provide feasible technical means for realizing differentiating tongue to test constitution.