A silver bullet was a bullet made of silver, used as ammunition in a firearm such as a gun.
When the Scooby Gang learned there was a werewolf loose in Sunnydale, Xander figured using silver bullets to kill it. Gib Cain was seen casting silver bullets while preparing to hunt and kill the werewolf Oz, employing a rifle to fire them. Kennedy used a gun loaded with silver bullets in the battle against Evolved Vampires and noted they were doing the job, although she said this may have been because she was essentially decapitated them.
- Cain's bullets were identified as silver in the "Phases" shooting script.