Anyone ever use this? http://www.airbornehealth.com/

I have had a miserable cold since Christmas. It just won't give up. I've been taking mega doses of vitamin C (5000+ daily), plus echinacea, and my multi, and it's not touching it. Yuk. I just got some of this effervesent herbal formula, but then read it should be started at first signs of a cold. eek... How about almost two weeks into it?! I figured it can't hurt to try anyway, but was wondering if anyone has used it?