My doctor first put me on 250 mg 3x a day, i was only able take it 2 x a day, because I would have had to either take it to early in the morning or too late at night to fit the 3rd pill in and I need to eat when I take it.. it was tolerable, now he has me taking 500 mg 2 x aday and I am feeling it. I called him yesterday and he said it sounds like your herxing try to stay with it and you will feel even better than before when you get through the Herx. I believe him because everything he has said to me from the begining which was a year and half has happened. My question is for you guys who have taken Flagyl, what were your results? Did you improve? Did your herx last long? what did you feel while you were taking it? Thanks for your help looking forward to your response.