Never had one, personally, but they probably don't work anymore. The bacteria are building more and more resistance. I went to urgent care years ago... stepped on a roofing nail that punctured my foot. I just wanted a tetanus shot, since I was way overdue, and of course it was the weekend. Flaky dr insisted on looking at the wound and then prescribed me a huge course of antibiotics... even wanted to give me a shot. I refused, didn't think it was necessary, as I made the wound bleed as much as possible to clean it out. That, and the nail went through the sole of my tennies and a clean, thick sock. She kept insisting and I said I thought we weren't supposed to use antibiotics unless we really need them. She gave up then, but gave me the paper and said to start them if the foot got infected. Yes ma'am. Foot was fine. No infection.