When I was a student in pharmacology, I remember reading about the side effects of digitalis. Digitalis is a drug that is derived from foxglove, the common garden ornamental plant. The side effects included several stages that helped a doctor to recognize when too much digitalis was given, so that the dose could be reduced to prevent killing the patient.
Eventually digitalis was synthetically made, and all those stages of overdose disappeared. You either had the dose right and helped the person with their heart failure, or you potentially killed the person. The stages of overdose originally came from using digitalis in its plant form! There were all sort of other active principles in the plant prep that warned that the dose was too high. I’ve often thought about this example and its comparison to the use of single agent drugs in modern times.
Plant medicines aren’t just one component. They have several components that can be part of the effect of the plant. This is not just true in the “warning” sense but also in the therapeutic sense. Plants can have more than one effect on multiple systems in the body.