i started saccharomyces boulardii on Sunday. gave me a headache that day, and everyday since, and also a bit of a runny nose. and about Tuesday it broke my face out a bit, but i stayed on it and my face is almost clear again. the headache i still have. i tested negative to yeast sensitivity a while back, and ate gf bread with yeast in it, with no prob that i recall. also i took 12b count. i think i'll drop to 6b. anyways, don't have an answer for you but maybe your sensitivity will decrease. if not, i wouldn't take it. i would assume it would perpetuate a leaky gut if you are intolerant.