The demon curing ritual is a ritual that can be used to cure a demon without any significant damage to the vessel. It has been performed successfully two times.
Procedure & Incantation
The procedure was originally invented by Father Max Thompson back in the 1950s. After 18 times failed, finally, he founded the proper formula to curing demons. It involved purifying the blood of a human. The demon is trapped in a devil's trap drawn on any consecrated ground. The purified blood is drawn into a syringe and plunged into the demon's neck eight times, once every hour. The ritual's effect is not instantaneous. Until the fourth hour, the demon is still the one in control. It was after the sixth dose that any change was visible. After the eighth dose, the person who is performing the ritual has to recite an incantation, a variation of the exorcism incantation,
"Exorcizamus te, omnis immundus spiritus. Hanc animam redintegra, lustra! Lustra!".
His palm is slit and the palm is placed against the demon's mouth. White light engulfs the demon and a second later, the demon is cured. The demon becomes human again as a result.
Another version of the ritual is performed by having a priest bless the blood for purification instead of it being purified by repenting sins. The blood is then injected into the demon eight times, but unlike the other variant, this one does not require the exorcism portion with the demon becoming cured after the eighth dose.
Although Father Max Thompson was a little weak from losing blood every hour, the after effects on Sam were worse as he was already quite weak, due to completing the first two trials. Every dose administered to Crowley, caused his arm to glow orange and caused him pain. As a result of Sam not finishing the ritual, Crowley did not become human again but did retain human emotions and an addiction to human blood.
If the treatments are terminated for a short while, as the demon being cured gets closer to human, devil's traps and consecrated ground lose their effect on them as do binding cuffs, allowing them to free themselves.
- This ritual is the third and final trial to close the Gates of Hell.
- The way the demon is cured is similar to way an angel smites a demon but without killing the vessel, though when Dean cured, there are no bright flash like when Father Thompson cured Peter Kent.
- When Sam cures Dean, he doesn't put a bloody hand over his mouth and do the incantation but the cure still works.
- When Sam cures Dean, he uses blood blessed by a priest as the purified blood rather than his own purified by confession like he did with Crowley.
- Dean is affected badly by the ritual, with it causing him great pain, either because he's a Knight of Hell or because of the Mark of Cain, or it could be a combination of both.
- The ground the ritual is performed on has to be consecrated, however, it can be consecrated through a ritual rather than be preexisting consecrated ground.
- Father Max Thompson (successfully cured the demon possessing Peter Kent)
- Sam Winchester (unfinished, on Crowley, successful on Dean Winchester)
- Some fans speculated that Sam might attempt to cure Dean in Season 10. However, the problem with that scenario is that the ritual might not work on a Knight of Hell with the Mark of Cain, such as Dean, since Dean (and Cain) are immune to rituals and weapons that work on normal demons. This theory is proven correct as Sam does cure Dean in "Soul Survivor." It works but he fights it, escapes briefly and tries to kill Sam before being recaptured by Castiel.
- There is one theory that Dean was not fully cured by the ritual, and is instead biding his time, healing himself. This is unlikely however as holy water had no effect on him after the ritual was completed and it was shown that holy water did effect the demon Dean.