Blood

Blood is an important component in many rituals, weapons, spells, and other aspects of the supernatural world.

Rituals and spells

 * Creating an Angel Banishing Sigil: Requires Human blood or Angel blood
 * Using the Goblet of Blood: Requires fresh blood from a human victim.
 * Summoning a demon that was previously exorcised: Requires the blood of the original exorcist. (Repo Man)
 * Angel-tracking ritual: Castiel uses this to track down Balthazar. This ritual requires human. (The Third Man)
 * Soul-proofing spell: Requires the blood of the soulless person's father - or the equivalent of a father. The father must also be killed. (Appointment In Samarra)
 * Summoning Samhain: Requires three blood sacrifices.
 * Opening a portal to Purgatory: Requires the blood of a creature native to Purgatory.
 * Restraining spell: Kali used Sam and Dean's blood to cast a spell that prevented them from escaping the hotel.

Weapons

 * Bone Of Righteous Mortal Washed In the Three Bloods of Fallen: Requires blood from a Fallen Angel, an Alpha, and the current King of Hell.
 * Dead Man's Blood: Can be used to incapacitate Vampires.
 * Vamp-Tonite: It will kill Vampires, Werewolves, Ghouls and other creatures that feed off of humans, except for Leviathan.
 * Sword of Bruncvik: Forged in Dragon's blood.
 * A Djinn can only be killed by a silver knife dipped in lamb's blood.
 * Veritas could only be killed with a knife dipped in a dog's blood.
 * Chronos could only be killed by an olive stake dipped in the blood of "You don't want to know."
 * Tricksters can only be killed by a stake dipped in the blood of one of their recent victims.

Other uses

 * Angelic Possession: Angels can only possess humans of certain bloodlines. This is especially true of the Archangels.
 * Croatoan Virus: This virus is passed through blood contact.
 * Food: Certain creatures, namely Vampires live off the blood of humans. Some demons, like Lilith, also drink human blood.
 * Demon blood is needed to charge the Special Children's powers, as well as for a vessel to contain Lucifer.