Review on Processing Methods of Toxic Chinese Materia Medica and the Related Mechanisms of Action

Toxic Chinese materia medica (CMM) has both pharmacological activities and toxic effects. Based on thousands of years of experience in the application of CMMs, people have explored many practical processing methods of CMMs, also known as "Pao Zhi", to reduce/control toxicity and preserve/enhance efficacy. Toxic CMMs have been used throughout China's hospitals. Yet, the production and use of toxic CMM should be carried out in accordance with the Chinese pharmacopoeia (ChP) and the processing regulations formulated by the health administrative departments of provinces, autonomous regions, and municipalities directly under the Central Government. This paper summarizes the current understanding and awareness of toxicity and 45 toxic CMMs, the commonly used processing methods of toxic CMMs recorded in the 2020 edition of ChP, and the changes in the chemical component, toxicity, or efficacy profiles after processing. This review may provide useful information for the processing methods of toxic CMMs worldwide. We believe that with an in-depth study and understanding of toxic CMMs combined with a standardized application, the toxicity of CMMs will be predictable and controllable in the future.