I think everyone understands that plenty of things in nature are poisonous or dangerous in other ways.
But it's also reasonable to trust our intuition that food is generally better - i.e., more easily digested and more nutritionally complete - the closer it is to its natural form.
In the linked article, the supplement in question was was far from natural; it was highly refined and concentrated.
So the cause of the damage in this case was not from consuming a natural product, but from taking a highly _unnatural_ product.
If he'd just had ordinary green tea (i.e., dried tea leaves steeped in water) once or twice a day, as millions of people have done for many generations, this would not have happened.
The author, a junior doctor at the time, later acts the consultant what plant he was referring to and the consultant says "a water lily".
I think the consultant in question had a bit of a thing about people consuming large quantities of "natural" products and being surprised that this could make them quite ill and indulged in a bit of a rant.
There actually is a tree which will kill you if you hang around it for long enough (the manchineel tree), but to be fair I wouldn't expect to find it in somebody's garden.
Slightly surprised that tree isn't native to Australia - I guess though that pretty much any tree of a decent size will potentially kill you if you stand under it long enough!
But it's also reasonable to trust our intuition that food is generally better - i.e., more easily digested and more nutritionally complete - the closer it is to its natural form.
In the linked article, the supplement in question was was far from natural; it was highly refined and concentrated.
So the cause of the damage in this case was not from consuming a natural product, but from taking a highly _unnatural_ product.
If he'd just had ordinary green tea (i.e., dried tea leaves steeped in water) once or twice a day, as millions of people have done for many generations, this would not have happened.