Well it could still be from the potato chips, did he have alot of them? It's great that he has a vet appointment today..good for you. Anytime ******* has the runs I don't feed her for 24 hours. Then only very small amounts for the next 24 hours. Some people give lean hamburger and rice. When I worked for animal control we had a parvo. outbreak. I find it has a distinct smell. The dog's are very weak and the diarrhea is pretty constant. Are his vacc. up to date? Good luck and let us know what the vet says.