Cures

There are several cures for the transformation of humans into various beings.

Demons
Using a ritual created by Father Max Thompson involving injecting doses of purified blood and a modified exorcism can change a demon back into a human. This is referred to as "curing a demon."

Lance of Michael
In order to cure the Lance slowly poisoning an angel to death, the Lance must be broken as the Lance's power is in its craftsmanship and spellwork.

Mark of Cain
While preparing to use a spell to remove the Mark of Cain from Dean Winchester's arm, its repeatedly referred to as curing Dean of the Mark and its effects.

Nachzehrer
Killing the alpha of a Nachzehrer pack turns everyone that the pack alpha has changed back into humans.

Rabids
Exposure to holy fire, even through being trapped in a circle of it, will cause the Rabid infection to burn away.

Vampires
If a vampire has not yet fed on even a single drop of human blood, a cure can be created with the blood of the vampire sire that will reverse the vampire's transformation.

Werewolves
The British Men of Letters were able to create an experimental cure to lycanthropy using the live blood of the sire werewolf. It has only had one successful use. A previous attempt to cure a werewolf was unsuccessful and it was believed that no cure existed.

Borderwalker
In Supernatural: Coyote's Kiss, a Borderwalker could be cured by ingesting the blood of the Alpha Borderwalker.

Appearances

 * Season 6
 * Live Free or Twihard (Vampire)
 * Season 8
 * Freaks and Geeks (Vampire)
 * Clip Show (Demon)
 * Sacrifice (Demon)
 * Season 9
 * Alex Annie Alexis Ann (Vampire)
 * Season 10
 * Soul Survivor (Demon)
 * Season 11
 * Form and Void (Rabids)
 * Baby (Nachzehrer)
 * Season 12
 * Ladies Drink Free (Werewolf)