A Werewolf Bite is an extremely poisonous and toxic fluid that is produced by the saliva glands within a werewolf's mouth. The venom is commonly injected into vampires as a means of infecting and eventually killing vampires.

Whenever a vampire is bitten by a werewolf, the poison will be passed from the werewolf's mouth into the vampire's bloodstream. Once the blood is contaminated by the toxic fluids, the vampire's heart will pump the venom throughout their cardiovascular system which will cause the venom to infect every cell it passes within the body. Over the span of approximately one week, the venom will have saturated all cells within the body, and will the cause the vampire to die a slow and painful death.

Werewolf bites can not kill an Original as Elijah mentioned to Elena when they were talking about how to kill Klaus.

The Cure

The only cure that is known is the blood from Klaus. Klaus blood is the cure for any Werewolf or Hybrid bite.