I know that acidophilus is good to take while humans are on antibiotics...you might ask the vet about a kitty formula...just make sure that it contains LIVE cultures. My sister had a cat named Sophie years ago that died because of some type of thread that she had eaten. I think that it got tangled around in her intestines and actually blocked one. They didn't find it though until it was too late. You and Jimmy got lucky that he was able to pass all of that gunk and move on...YAY!...Glad to hear that he is feeling more frisky!!