Hydrogen peroxide. Hydrogen peroxide, (H2O2), a colourless liquid usually produced as aqueous solutions of various strengths, used principally for bleaching cotton and other textiles and wood pulp, in the manufacture of other chemicals, as a rocket propellant, and for cosmetic and medicinal purposes.
When peroxide is swallowed, it generates oxygen bubbles in the stomach. There can be a lot of stomach irritation and even burns that require a trip to the emergency room and possible hospital admission. Drinking higher concentrations of hydrogen peroxide can be very dangerous because it can cause tissue burns.