4. Hydrogen peroxide
Florida resident Bill Thompson claims he hasn’t had a cold in more than 20 years. His secret? Every morning he fills his sink with diluted hydrogen peroxide, dunks his head in and blows bubbles through his nose. Sounds crazy, yes—but, Stone writes, hydrogen peroxide uncontroversially helps heal wounds by killing surrounding bacteria, and not a lot of research has been done on its other potential health benefits. Just be careful if you try it: concentrated hydrogen peroxide can be dangerous, and even diluted it can bleach your clothing and other materials; it also should not be ingested.