The riddles of number nine in Chinese medicine processing method

The “nine cycles of steaming and shining”, “nine making”, “nine turns” and “nine cycles of calcining and quenching” methods that are recorded and used since ancient times are merely one aspect of the unique processing methods of traditional Chinese medicine. Inducing the Chinese medicine processing method “nine cycles of steaming and shining” from historical review and summarizing the practical wisdom based on the canonical aspects of traditional Chinese medicine and the experiences of ancient Chinese medicine sages to promote the new development of traditional Chinese medicine. After the long-term and multiple “nine” processing, the materials of traditional Chinese medicine exhibit significant beneficial changes in terms of taste, efficacy, and chemical composition contents, thus emphasizing that Chinese medicine processing plays a significant role in their efficacy enhancement and toxicity reduction. Heshouwu (Polygoni Multiflori Radix), Dihuang (Rehmanniae Radix), Huangjing (Rhizoma Polygonati), Dahuang (Radix et Rhizoma Rhei), and Xixiancao (Herba Siegesbeckiae) are representatives of Chinese medicinal materials prepared using the “nine-system” processing method. This review discovers the aim and the molecular mechanism of “nine” processing of the abovementioned herbs from the viewpoints of modern pharmacochemistry and pharmacology to provide a theoretical support for the “nine” processing method of traditional Chinese medicine and to promote the international market of traditional Chinese medicine.