Hi All:

This maybe helpful to you as a guide when purchasing your h202. 

http://www.alternativehealth.co.nz/cancer/oxygen/peroxide.htm

The 3% hydrogen peroxide (H2O2) available in grocery stores and drug stores contains stabilizers (such as phenol, acetanilide, sodium stanate and Tetrasodium phosphate). This hydrogen peroxide is for external use only, not for internal consumption. It is OK for brushing the teeth, gargling and as a mouth wash, providing you rinse your mouth after.

The 35% food grade hydrogen peroxide is for internal consumption and can be diluted for intravenous application. See oxygen therapy international doctor and clinic list.

Other grades of hydrogen peroxide include 6% used by beauticians and contains bleach, 30-32% electronic grade used for washing electronic parts, 35% technical grade which contains a small amount of phosphorous, and 90% used as a source of oxygen in rocket fuel.