The eighteen incompatible medicaments and nineteen counteraction theory belongs to the category of compatibility contraindications in Traditional Chinese Medicine(TCM),and has been used as a basis for rational evaluation in the review and evaluation of TCM prescriptions for a long time.However,there is constant controversy on the theory from perspectives of the historical origins,content categories,modern research,clinical applications,and ancient and modern academic.Thus the author gathered opinions medical and pharmaceutical experts from various types of medical institutions across the country based on literature review,expert interviews,and questionnaire surveys.The improved Delphi method and evidence review evaluation system were used to classify and understand,the eighteen incompatible medicaments and nineteen counteraction theory in a hierarchical manner.The core principles of this theory were analyzed using a classification model of"toxic-toxic"combination,"toxic-non toxic"combination and"non toxic-non toxic"combination.The recommendations for clinical safety risk assessment were formed on various types of evidence.The final consensus consists of three parts and a total of 19 statements,aiming to provide reference for the scientific and rational use of herbal medicines and the high-quality development of the industry.