That's quite true. All plants have a phytochemical profile. The body has to metabolize those chemicals and some combinations of them create different chemicals and consequently different challenges for the body. I forget now which old Greek said "the difference between a medicine and a poison is the dose" but it could also be said in many cases "the difference between a food and a medicine is the dose." It can also be the difference between your personal metabolic constitution, your condition and the particular substance/s you are ingesting.
I have said the same if not in the exact words here many times. It all comes down to dosage.
I am by no means a nut about health - I'm having my 2nd Seven & 7 right now and may enjoy a pipe- but control, moderation and balance, just a few things that will take you far.