Yep, you sure can
Sted had diarrhea after we took him in for his first set of shots. I started freaking out as my best friends Yorkie had Parvo at was at my house a little over a month before we brought Stedman home, so I called the vet and asked him about it. He said that most likely it was from the shots since it wasn't TOO runny (it was mainly just loose stool), or bloody. I told him that all I had on hand was Pepto and he said that it would be fine to give him. I'm pretty sure it was 1 tsp that I gave him. It helped him and he had no more "runny stuff" after that
