Colorful Diagnosis

AI-powered tongue analysis borrows from traditional Chinese medicine

- Eve Lu

FOR THOUSANDS OF YEARS traditional Chinese medicine (TCM) practitioners have checked patients’ tongues as part of a full examination, carefully scrutinizing their color, shape and coating in an attempt to detect illness. TCM considers a tongue’s color especially telling—and now some researchers, encouraged by recent studies pointing toward a measurable association with health factors, are working to adapt this ancient diagnostic approach to today’s AI-based technology.

TCM remains a controversial topic in the global scientific community. The World Health Organization officially added TCM diagnoses to the 11th revision of the International Classification of Diseases, the global standard for health-information classification, in 2022. But most high-profile studies have treated the topic warily. “Despite the expanding TCM usage and the recognition of its therapeutic benefits worldwide, the lack of robust evidence from the EBM [evidence-based medicine] perspective is hindering acceptance of TCM by the Western medicine community and its integration into mainstream healthcare,” wrote the authors of a 2015 review article on TCM’s prospects. Still, pockets of strong academic interest persist.

In TCM, tongue color “is closely linked to the condition of the blood and qi [a Chinese term often translated into English as ‘vital energy’], making it a primary indicator for TCM practitioners in assessing a patient’s overall health,” says Dong Xu, whose research at the University of Missouri focuses on computational biology and bioinformatics and who coauthored a 2022 study on analyzing digital tongue images. But tongue examination can be highly subjective: it relies entirely on an individual practitioner’s color perception and analysis.