What is 5, and why are we so certain that it's more than 3?

I asked this question a while back about the effects. It doesn't answer your question, but it turns out that nobody called it a contraceptive until a hundred years after it went extinct. Assuming it wasn't a totally ineffective treatment, it was, at best, a seriously toxic plant that would hopefully kill the baby before the mom.

Sorry, are you actually suggesting that lying to the public is the better long-term option?