giardiasis
"500 mg 3x a day for 10 days only made it to pill 6.  Horrible side affect.  Headache,  nauseous, no appetite causing weight loss,  white gunk in eyes,  liquid in ears,  itching skin, swollen sore mouth with tinfoil taste, vaginal yeast, low back pain, blurred vision, ovary pain(though no problems with ovaries before), inflammation. This sounds like an allergic reaction but what it was is this medicine ignited a whole body yeast infection like a atom bomb by day 2. Had to stop taking it because the medicine is 10x worse than the guardia is. I'm sure it's definately toxic to guardia if you can survive the duration of the treatment"