I had already decided to recommend the BRAT diet when I read your other 2 responses. So, I third that response. Bananas, Rice, Applesauce, Toast. You can also give crackers and somewhat bland protein like chicken breast. Dairy may or may not be contributing to your problem, but you may want to try cutting it out completely until this passes in case it is. Give pedialyte to replace fluids lost due to the loose stools. Yes, he had a cold. But, earlier, my 18 month old had a virus that caused a cold and gastrointestinal problems at the same time. Then I got it, too. It lasted a while, but wasn't horrendous. You could also google the BRAT diet to see what other options that fit into that category are out there. Good luck. It is never fun with an under-the-weather child. I would hold off on the potty training until this is all over and done with.