Hello, rebecca_jack23, Hope your urinary tract infection is better. Some of the antibiotics that are used can cause either constipation or diarrhea as a side effect. Ampicillin types give more diarrhea and the Floxacin types can do either. I think since you were constipated , I think you might have a little impaction of the stool in the rectum. I would advice that you try taking a plain fleet enema and see if this clears. Seapage around an impacted stool is seen often. Bu t if the diarrhea becomes worse, you may have to stop the antibiotic and discuss with your doctor. We have to think about another antibiotic induced colitis called C.Difficile colitis. Wish you well.