I have recently read too that peppermint is recommended after meals for gas and bloating (I posted an article on it earlier this week or last week). Maybe you should try peppermint candies? I daresay they aren't as concentrated and I've never heard of anyone vomiting up a peppermint candy.
And yes, taking it on an empty stomach would not be good. You should take one, I would think, right after a meal; I think that's what the article recommended.