Is whitening your teeth with pure hydrogen peroxide safe? what happens if i swallowed a tiny bit by accisdnt?

My burn some: Hydrogen peroxide will actually convert to water after it released its oxygen.The teeth whitening products will burn a bit going down if you swallow some but other than transiently irritating the tissue should cause no long term problem.

Not really...: I suspect you don't really mean pure hydrogen peroxide, which is highly explosive, but rather the 3% hydrogen peroxide solution intended as a topical antiseptic. This product is far too dilute to whiten teeth, but may irritate or burn sensitive oral soft tissues, and provoke a condition known as "hairy tongue". Swallowing small amounts may induce nausea, but are unlikely to otherwise be harmful.