Step right up, folks. This miracle in a bottle will cure everything from dandruff to cancer."" In the nineteenth century you might have heard this pitch on a street corner from characters we called snake oil salesmen. Today quack remedies are sold by celebrities on electronic media. Suzanne Somers, Gwyneth Paltrow, Kim Kardashian, and a host of other “bold face names” promote questionable products and health advice via TV appearances, apps, and web sites. The modern market for useless health products—snake oil—thrives in a swamp of advertising hype and pseudoscience. We swallow what marketers sell even when the claims are preposterous. Who actually knows what works? What’s the difference between science-based medicine and everything else? Which health news is “fake” and who should you trust? The answers are in these pages.