Be careful, peroxide is very potent! Are you following the correct protocol? You should start with only 1 to 3 drops of 35% peroxide in 8oz (1 cup) of water, if this is too much, you'll have to dillute it in even more water. Eventually, you'll be able to work up to higher doses. If you have an active stomach or intestinal infection, the rapid oxidation of the candida/bacteria/etc can be very uncomfortable! If this happens, decrease the concentration. Also, you need to always take it on an empty stomach, at least three hours (or even longer) after eating.