2  Methods

2.1  Data sources
The following data sources were searched on February 25, 2020 for eligible traditional medicine guidelines and searched up to March 6 to retrieve the updated version of the guidelines provided:• Guidelines International Network (G-I-N)8
• “Chinese guidelines on Novel Coronavirus” resources9 by Evidence Aid
• The official government websites of all 31 provinces in mainland China (including municipal and autonomous regions)
• The Centre for Health Protection of the Hong Kong Special Administrative Region10
• Association of Korean Medicine and Korean Association of Traditional Pulmonary Medicine
• Japanese Association for Infectious Diseases and Japanese Respiratory Society11
• Taiwan Centers for Disease Control12

2.2  Inclusion and exclusion criteria
This study focused on the recommended treatment modalities related to traditional medicine for COVID-19. All guidelines that provide traditional medicine treatment measures were included regardless of language, and publication types and years. Guidelines that only provide preventive measures without treatment measures were excluded.
Herbal formulae related to folk medicine were excluded only and other herbal formulae in these guidelines were included. As the guidelines were outlined based on regional characteristics, regional folk medicines, such as Tibetan medicine in Tibet, Mongolian medicine in Inner Mongolia, and Miao medicine in Guizhou province, were integrated into their guidelines.

2.3  Data extraction and analyses
The data from each included guideline were extracted using a predefined data extraction table. The content of the data extraction tables comprised the stages of the disease, pattern identification, clinical symptoms, therapeutic principle, name and composition of herbal formulae, amount of herbs, and country or province of the provided guideline. The pattern identification and herbal formulae were analyzed according to the severity of the disease (mild, moderate, severe and recovered stages). The frequency of herbs recommended in the herbal formulae for each stage of disease was also computed and analyzed.

2.4  Terminology standardization
The terminology of pattern identification were standardized based on the clinical manifestation provided in the guidelines and Clinic Terminology of Traditional Chinese Medical Diagnosis and Treatment-Syndromes.13 The herbal formulae with missing names were also renamed by comparing the compositions of these herbal formulae with other named herbal formulae and double-checked them with the Dictionary of Traditional Chinese Medicine Formula.14 All the terminologies were also standardized based on the WHO international standard terminologies for traditional medicine.15