I'm a 26 year old male who weighs 200 lbs. I was diagnosed with Giardia on July 14 and my doctor prescribed me Flagyl (500 mg x 3 times/day for 5 days). One of the side effects of the Flagyl is Diarrhea. Upon taking the medication, my symptoms, bloating and gas disapeared. It's been 2 days now that my dosing is complete, and I'm starting to have diarrhea and gas again (not to the same degree as it was before). My doctor Prescribed me an emergency Rx incase of relapse. Based on symptoms, should I start this prescription, or see if it dissipates. I leave the country in exactly 1 week, and would like not to have to fly with the fear of a potential diarrheal attack...