Bev - are you measuring the dose with baking teaspoons/tablespoons? And are you using level instead of rounded teaspoons/tablespoons? You might actually be up to a pretty high dose already without realizing it.
I figured this out just recently when talking to a woman who said she was taking three teaspoons a day, and that had pretty much resolved all her symptoms. I thought that was interesting because that wouldn't be anywhere near a high dose (that would be more like 3 tablespoons a day). But - it turned out that she was using a teaspoon that you'd eat with, not a measuring teaspoon, and she was using a heaping teaspoon at that. So, she actually was taking about 3 whole tablespoons a day if you took an exact measurement.
Anyway, let me know what exact dose you're up to. You should be able to increase your current dose by a good teaspoon (baking teaspoon, level not rounded) a day since you've been on it for three weeks at this point.
Best, Heather
-------------------- Heather is the Administrator of the IBS Message Boards. She is the author of Eating for IBS and The First Year: IBS, and the CEO of Heather's Tummy Care. Join her IBS Newsletter. Meet Heather on Facebook!