This has only happened to me twice in a lifetime of IBS (beginning when I was in junior high--I'm now 44), but I woke up at about 4 am with intense abdominal pain. While I was sitting on the can with the Big D, I had cramps so painful they made me dizzy. My mistake was thinking I might just shift off the toilet seat and lie down...Next thing I knew, I was coming to with my face smashed in the floor and a whopping big laceration in my lower lip. The thump was so loud it woke my wife, who by now is used to my early am trips to the porcelain altar. The big cut in my lip healed (without stitches) in about ten days, but SHEESH. What a rude awakening! It was like getting wakened up from a comfy, warm bed just to have my lights punched out by my own body. This sucks!A lesson learned the hard way: Dizzy on the can means head between the knees. If it's ever this bad again, I'll be sure to bring a pillow.