The chinese medicines used in combination must be mutually compatible . the so - called " eighteen incompatible medicaments " and " nineteen medicaments of mutual antagonism " describe the specific chinese herbs which cannot be used together in a prescription . otherwise , toxic effects will be resulted 中药之间的配合,有十八反、十九畏之说,即是某些中药不可配合使用,否则有可能产生毒性反应或副作用。