Sorry should have mentioned we got that medicine to, but I though that was for the worms.My puppy (well hes almost a year haha) has Giardia again, he had it when he was 10 or 11 weeks old as well. You should have been given Metronidazole? They need 7-10 days of it in order to treat it. Keep your dog away from possible sources of infection (infected feces/water/soil) For puppies, it can be serious because of the diarrhea, so I am wondering why they didn't give you drugs to treat it? It can reoccur, so reoccurring infections are common. But you need drugs to treat this, or else it is not going to go away on its own.