Vampires are not particularly affected by silver bullets. Traditionally what kills vampires is a wooden steak through the heart.

What do silver bullets do?

It is used for the relief of occasional constipation. It can also be used for the preparation of certain medical tests (e.g., colonoscopy), before and after surgery, and in other situations where a bowel movement to required. It works by stimulating the bowel muscles and also accumulates water in the intestines.

Do silver bullets affect werewolves?

In folklore, a bullet cast from silver is often one of the few weapons that are effective against a werewolf or witch.