I figured there must be some nutritional reason behind it. I drank nothing but grape juice for a day and a half, and I have to say I did feel better that second day, but the next day was horrible. I had picked up a cold (my wife is a nurse and is always bringing these wonderful bugs home with her) so maybe that was part of it. Coughing makes my head hurt like crazy. I'll keep drinking the grape juice though. I do love the stuff. Thanks for the tip Christine!