By Namwook Cho, L.Ac.
South Korea has established the world’s first national reference standard for tongue color in traditional medicine.
Developed by the Korea Institute of Oriental Medicine (KIOM), the dataset standardizes tongue body and coating colors based on age and gender. Experts believe the findings can also be applied to clinical and digital health settings worldwide, including in the United States.
Korea Establishes National Reference Standard
for Tongue Diagnosis
The Korea Institute of Oriental Medicine (KIOM) has recently announced the development of a national reference standard for tongue diagnosis. It is considered the first official standardization of tongue color measurement in traditional Korean medicine (TKM).
Although the study was primarily conducted on Korean subjects, experts believe the findings can be broadly applied in the United States without significant limitations.
Historically, tongue diagnosis has relied heavily on observers’ subjective assessment, making it vulnerable to subjectivity and diagnostic uncertainty. Despite the availability of digital tongue diagnosis devices, a lack of standardized data hindered their clinical use and commercialization.
To address this, KIOM’s Tongue Diagnosis Data Center—officially designated as National Reference Standard Center No. 63 in January 2023—undertook a comprehensive study to standardize measurement methods and account for uncertainty across all existing tongue diagnosis devices in Korea. The result is a scientifically validated national reference dataset of tongue body and tongue coating colors, categorized by gender and age for healthy Koreans.
The standard was developed using 967 validated images selected from 2,158 healthy Korean tongue images, collected through standardized procedures during national health screenings.
This initiative strengthens the scientific credibility of TKM diagnostics and is expected to support future clinical studies, AI-based digital health tools, and the commercialization of diagnostic technologies.
The national reference standard was officially registered on December 19, 2024, on the National Reference Data Platform (www.srd.re.kr), and the research findings were published in the Journal of Standards, Certification and Safety on June 30, 2025.
KIOM researchers expressed optimism that this achievement will enhance the reliability of tongue diagnosis and expand its application in clinical and digital healthcare settings.
