Hemlock or Conium is a highly toxic flowering plant indigenous to Europe and South Africa. The ingestion of 100mg of conium or about 8 leaves of the plant is enough for the effect to take place.
Aconite comes from the plant monkshood. Poisoning for vampires will occur if it is ingested or forcefully introduced into his system( Poisoned blade/arrow ). Attention! Humans can be poisoned by touching the very leafs if they aren't using gloves.
The name of this plant is derived from Italian and means "beautiful woman". if ingested, a single leaf is lethal and that’s why it was used to make poison-tipped arrows. The berries of this plant are the most dangerous – consumption of ten of the attractive-looking berries is enough for the effect to take place.
Firstly, it is found in a great variety of substances like almonds, apple seeds, apricot kernel, tobacco smoke, insecticides, pesticides and the list goes on. The required dose of cyanide for the effect to take place is 1.5 mg per kilogram of body weight. Secondly depending on the dose, the effect occurs within 1 to 15 minutes. Also, in its gaseous form – hydrogen cyanide – it is not effective.
Arsenic has been called “The King of Poisons”, for its discreetness and potency – it was virtually undetectable, so it was very often used either as a murder weapon or as a mystery story element.
***Note: Other poisons that have the effect taking place after a long period are not effective against vampires because the vampires are burning the toxins quick enough by burning vitae.
Note II: Those are a few examples of common poisons.