I have dealt with diarrhea in a beagle and a cat and, after about 3 days, if it has not resolved I recommend seeing the vet. Diarrhea can take on a life of its own after a while and sometimes they recommend something to break the cycle. You may want to ask about Propectalin (like Kaopectate for animals.) (BTW-Don't give real Kaopectate because it has salicylates in it which is dangerous for them
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Good luck.