Oh wow so many things can cause a bout of diarrhea. I agree with other people here on the thread that you should definitely chat with your vet to make sure there isn't something serious going on. After that, one of the best things you can do for a dog that is having diarrhea is give him a probiotic such as Fortiflora. What a probiotic does is help to normalize the digestive tract and put back in healthy bacteria. It's also really important to note that Fortiflora can be used on a daily basis to stave off diarrhea, increase digestive function as well as the immune system. Probiotics are great for so many things. I hope your dog's diarrhea gets better!