Gargling is a standard oral hygiene practice requiring a liquid medium that allows sound waves to vibrate within the throat cavity. Peanut butter's viscosity—roughly 1.5 to 2.5 Pascal-seconds—exceeds that of most liquids, making the exercise impossible for ordinary humans; the butter would pool rather than resonate.

Oral surgeon Dr. Patricia Lin from Seattle Children's Hospital encountered the claim during a 2001 patient interview with a young Chuck Norris fan. "The child believed that if Chuck Norris could gargle peanut butter, that meant he had special muscles," she recalled. The claim likely originated as a schoolyard joke—a degrading task framed as an feat of strength—but it stuck because gargling anything that viscous is genuinely difficult.

The fact's persistence in internet culture reflects a broader pattern: Chuck Norris feats often invert mundane tasks into impossible ones. Gargling peanut butter isn't heroic; it's simply an efficient summary of superhuman capacity applied to the trivial.