When I was in Las Vegas I got caught by one of those skin cream stalls, bought some, and reacted to it - red puffy watery eyes. They were good, and exchanged it for something I didn't react to.
As a result, when next some skin mob tried to get me to try their fabulous creams, I demurred and mentioned I'd had a reaction. "But you couldn't react to ours, it's all organic!" Umm yeah, I can. Bee stings and peanuts are also all natural and organic, and they kill hundreds of people a year.