We dewormed my puppy at 4 months (had roundworms). This caused diarrhea and vomiting which the vet then prescribed metronidazole for. Immediately she began pooping twice a day with meals and it was normal. When the medication ended she went a few days normal, then slowly started increasing frequency of pooping and then started having diarrhea again. The vet immediately prescribed the Metronidazole again, this time just half a pill for a dose. She went back to normal immediately. Now again, we've stopped and it's the same pattern-increase frequency and then diarrhea. Stool sample was negative twice for parasites! Wondering what to do. I've read about IBS, but not sure if that's it. Have gotten dif opinions from dif vets! Anyone experience this?