Eighteen Incompatibles & Nineteen Antagonisms

CORE DEFINITION

The Eighteen Incompatibles and Nineteen Antagonisms are incompatibility taboos in traditional Chinese medicine. Mixing certain drugs can enhance their toxic reactions or side effects, affecting health or even endangering life. According to the compatibility principles of Chinese medicine, 'incompatibility' means that the combined use of two drugs can produce or enhance toxic reactions or side effects; 'antagonism' means that the toxic reactions or side effects of one drug can be reduced or eliminated by another. Currently, the Eighteen Incompatibles and Nineteen Antagonisms are generally recognized as incompatibility taboos in clinical practice. However, famous physicians throughout history have often violated these taboos in their prescriptions. For example, Zhang Zhongjing's 'Synopsis of Prescriptions of the Golden Chamber' includes 'Gansui Banxia Decoction', which combines Gansui (Euphorbia kansui) and Gancao (licorice). Some medical scholars also believe that incompatible drugs, when used together, can produce a synergistic effect, enhancing efficacy. If used appropriately, they can cure severe and chronic diseases. Therefore, some argue that clinical medication should not be rigidly bound by these taboos. In general, since experimental research on the Eighteen Incompatibles and Nineteen Antagonisms is still in its early stages, it is premature to decide on their adoption or rejection, and further in-depth research is needed. Therefore, for drug pairs that fall under the Eighteen Incompatibles and Nineteen Antagonisms, unless there is sufficient basis and clinical experience, it is recommended that they generally not be used in combination. In the Jin Dynasty, Zhang Yuansu compiled the 'Eighteen Incompatibles' and 'Nineteen Antagonisms' into rhymes in his work 'Pearl Bag of Materia Medica', which became widely circulated and has been passed down to this day.