I don't drink the rooibos for IBS stuff. I just like it cause it tastes good! But, it is healthy with the antioxidant stuff, so it does have good side effects.
Fennel is what you want for gas & bloating. I order mine from Heather. I also can't stand fennel plain, so I mix it with peppermint. If you like black licorice flavor, you probably wouldn't mind the taste. But, somehow I have a feeling you'll have a big ol' EW! to that! LOL