Marijuana Alternative?

Lately I have been hearing a lot about legal marijana alternatives. Where I live a product called Black Mamba is all the rage. My friends tell me it is exactly like marijuana, but it contains no THC and is perfectly legal (you can buy it at www.smokeblackmamba.com) - my friend uses it regularly for her migraine headaches and loves it.

What do you guys think about this product? Is it a quality alternative to illegal marijuana? Have any of you tried it?