My four month old Shih-Tzu had diarrhea yesterday. I thought it was from dehydration because it was hot in Southern California yesterday, but this morning when he woke up to poop, it was mostly blood. I rushed him to the vet, where they gave him fluid under the skin and ran a fecal test, which they said came back negative. The vet started him on flagyl for the diarrhea anyway and told me to give him a "bland diet." Later the vet called back and said it wouldn't hurt to put him on medicine for giardia (sp?), which I did immediately. He has tried to poop twice since taking both medications, and both times only a drop of poop comes out followed by some drips of blood, which stain and smell his anus and the hair around it. He refuses to drink any water, and I've begun forcing it by giving it to him in a syringe. He's a little lethargic, as well. I'm going to follow up with the vet tomorrow, but I was wondering if anyone here had any ideas or second opinions about what it could be.