Vervain: Is a potent herb, and a vampire's most well-known weakness. If a vampire makes physical contact with vervain in any form, it will burn them. Including drinking the blood of a person that has ingested Vervain. (Human or otherwise) Vervain also protects the wearer against mind compulsion. (Something created by witches to help keep them safe from vampires.)
Ways to use Vervain -Put it in your food or drinks You can carry it by: -Holding it in your hand/pocket -Putting it in your bag -Wearing it in jewelry -Wearing it as a perfume