My pup had bladder infections when I first got her that were pretty bad. She did 2 courses of antibiotics about 10days each time. The first round wasn't strong enough so that's why it came back. The second round worked though. I started giving her cranberry extract power (Cranberry Relief by NaturVet) everyday since then as a preventative measure. I don't really know if it works but she hasn't had another one so I'm hoping it's helping!