So, I just wanted to find out if Panacur can cause diarrhea? Sorte just started a round of Panacur paste from the vet. Up until today, he has had soft cowpie stool with no leaking around the house. I gave him his first dose today and now he is back to multiple runny stool sessions with small spots of blood along with large leaky spots once again around the house. His vet is on vacation until sometime next week.