I am in my mid-forties and female. Off and on for the last 3-4 years (maybe once or twice a month), I will awaken at night, nauseated and lightheaded. I'll get to the bathroom, rest till the dizziness passes and then need to have a bowel movement(not necessarily diarreah.) Then, I'll go back to bed and usually be just fine the next morning. I had all kinds of tests done..colonoscopy, barium this and that, CAT scan, gall bladder test etc. but, nothing turned up. I altered my diet at night (since this just seems to happen at night)stopped drinking red wine, carefully avoided rich fatty foods/ice cream etc. (In the meantime, I developed migraines particularly during my menstral cycle although I don't notice a headache, necessarily, when I wake up in the night feeling sick but often do have one the next day.) Anyway, I thought I had it handled with diet since I didn't have an "episode" for a number of months when wham, I've had three such events in the last two months!(I am also on Elavil for my migraines..) The doctors suspect IBS but I know it's odd to be awakened by symptoms. Any ideas??? By the way, I am a "fainter" particularly when I am shocked emotionally or when I've had a bad GI bug. One doctor says my "lightheadedness" may be due to vasovaga (?)and may do a tilt table test for a final determination. But that doesn't explain needing to use the bathroom at night, does it? My weight is ok and I generally feel just fine during the day.