Vamptonite is what Sam and Dean nickname the blood of humans who have been eating foods laced with the leviathan modified corn syrup in 7.22 There Will Be Blood. The modified sweetener produced by SucroCorp renders people lethargic and causes overeating. When eaten by or injected into vampires it kills them.
The tainted blood is not harmful to leviathan, but Dick Roman plans that in addition to turning humanity into a well-fed docile food source, it will also eliminate other predators - notably werewolves, ghouls, shapeshifters, anything with a taste for human flesh.
- The term "vamptonite" is a play on the term kryptonite - an ore from the planet Krypton which incapacitates Superman.