I got massive uncomfortable gas from eating lots of Spry peppermint mints (about 15-20 at a time they are about the size of a tick tac). I assumed it was the zylitol which supposedly kills yeast. I had headaches too which I only get when I try to kill yeasts with antifungals. I felt better, clearer head, less rash etc after the die off so I tried to continue eating the mints, unfortunately my food starting coming out totally fermented and undigested so I quit. Maybe I should have continued, but Im underweight..