Interesting. In the US at least Crotons are rather popular as houseplants. I've kept them for years, and never knew of this property or story.

Assuming it's true, I wonder if any documentation exists at all from one of the affected souls on those subs.

A cursory search doesn't seem to turn up anything solid.

But it would be interesting to know. I'll be in the German diary archive in March and made a note to keep an eye out for it.