Hydrogen peroxide "oxygen therapy"

That cancer cells cannot survive in an oxygen-rich environment, so flooding the body with oxygen via hydrogen peroxide kills them.

Rests on Otto Warburg's 1931 Nobel-winning work on cancer cell metabolism, which is real science. The leap from "tumour cells metabolise glucose differently" to "drink peroxide" was made by mid-century alternative practitioners and is now sold as "35% food grade H2O2 protocols".

The Warburg effect is genuine and remains an active area of oncology research. It describes how cancer cells generate energy; it does not mean they are killed by ambient oxygen, and tumours are not anaerobic organisms. Hydrogen peroxide decomposes into water and oxygen gas on contact with tissue catalase. In the stomach that means rapid gas release into the portal circulation. Case series in emergency medicine journals document embolic stroke and death from ingestion.