YES! The cayenne CAN harm you if you already have problems with acid reflux. My advice is to purchase some gelatin capsules and put your powder into these. The capsules will get the cayenne into your system without setting your esphogus on fire! If you take the capsules and have any heartburn at all, try drinking a small amount od milk to tone down the capsicum a bit. Good Luck! (P.S.- You should be able to buy gelatin caps at your local health food store, if not, email me and I'll sell you a few at a wholesale price. I've got millions of them ;)