They should have it at Whole Foods or any health food store in the garlic section. It works well.
I think fasting can help with acute and chronic conditions. If you have fasted before, then you should be good to go, as you know what to expect and have experience. You definitely should have as good of nutrition as you can before fasting, but depending on how bad your condition is, you may only have to fast for a few days or so, so it may not be anything to worry about. You may find more answers on the Water Fasting forum.