I had extreme sensitivity to many things, and I had no problem at all with the Oxypowder . I did start really, really slow - 1 cap for a few days, then two for a few, etc. I did hear once of someone who had a rough detox on just one cap, but I've never heard of anyone else with that. If you are concerned, you could try splitting out a capsule and taking only a portion of one cap at first. It was really worth it to me to use this stuff. It's the most effective Colon Cleanse I've tried and it made a big difference. It enabled me to use other things I couldn't tolerate at all because of the herx effect.