Dead Man's Blood
A poison to vampires that incapacitates them for a short period of time. When the blood from a dead human is injected into a vampire it induces a blood sickness, causing them to become very weak.
The method of incapacitating a vampire with blood from a dead person is part of vampiric folklore. Tricking a vampire into drinking blood from a dead person to kill him has also been used quite a few times in vampiric tales, notably Interview with the Vampire, wherein the vampire must stop drinking the blood of her/his victim before she/he dies, as drinking blood after death is harmful to the vampire. In Supernatural, dead man's blood has been used as follows:
- John Winchester uses it in 1.20 Dead Man's Blood to restrain Kate, when he uses her as bait to lure out Luther and get the Colt. It's also used to take down Hank with blood-soaked crossbow arrows and later two other vampires who are all killed later.
- Samuel Campbell gives Dean a syringe of it when he goes to infiltrate the vampire nest in 6.05 Live Free or Twihard. Samuel describes it as enough dead man's blood to drop a linebacker "and then some." He fails to use it against Boris as a single drop of blood drips from the syringe and he senses it, but during his slaying of all the nest's vampires, Dean injects another vampire with it and presumably later kills him.
- The Alpha Vampire is given an intravenous drip of dead man's blood to restrain him in 6.07 Family Matters, and dead man's blood is spread on the doors of the building in which he is kept as a deterrent to other vampires. Despite the dead man's blood, the Alpha Vampire eventually escapes, though weakened and is brought down when the demon possessing Christian Campbell injects him with two syringes at the same time.
- When Sam and Dean decide to go after the Alpha Vampire for his blood, they initially decide to go looking for dead man's blood before coming on the idea of using "vamptonite" from people infected with the leviathan food-additive.
- When Dean and Benny go after rogue vampire Desmond, Dean grabs a syringe of dead man's blood from the Impala's trunk which is shown to be stocked with them. In the fight that follows, Desmond overpowers Dean and smashes the syringe, but it distracts him long enough for Benny to kill him.
- While hunting vampires, Krissy Chambers uses darts filled with dead man's blood to take down Jimmy Day who supposedly killed Josephine Barnes's family, allowing Josephine to kill him. Later, she shoots Seth, the vampire working with Victor Rogers in the right eye and chest with the darts, taking him down. This saves Aiden who Seth is holding hostage and allows the group to get his blood to create the cure for his last victim. The vampire is then presumably killed.