I have read quite a bit of information in relation to Grapefruit Seed Extract. Apparantly its not the grapefruit thats antifungal/antibacterial but the addition of a toxic chemical to the supplement called tricolsan that is basically a component of bleach - which kills the yeast/bacteria. I wouldnt touch GSE...I know I will get shot on here for saying it but research it yourselves. Grapefruit Seed Extract I think its banned in Germany and Japan deemed unfit for human consumption. Just because its so called "natural" doesnt mean its safe. Alot of supplements are full of toxic stuff. You are better off eating real grapefruits (if you can tolerate) - good for your liver!