I just started Allegra yesterday at 180milligrams. I took my first tablet and an hour and a half later, I became sick to my stomach and vomiting. About a half hour after that, severe diarhhea struck. I have had bouts with IBS in the past also. Has anyone else experienced this? I also took another new medication with it, so I am not sure which drug might have caused it. Anyone have any similiar symptoms or helpful hints?