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.