I've been having IBS-D symptoms for years. I went to the doc a few years back, and nothing conclusive, they just passed me off. Went again at the end of summer, and I was positive for giardia. Not sure where I got it, but I did. They put me on metrodonazil (or something like that...) and I noticed the giardia symptoms went away. My #### was different looking, my stomach would make a loud gargle... it was weird. But after the pills, I went back to having diarrhea all the time, but pre giardia symptoms. IBS D and giardia was NOT fun, at all. My guess is I've had IBS for years, and the giardia was just a coincidence. There was an obvious change after the meds, so, I doubt I still have it.