I just used one of these packs for the first time the other night, for 45 min, and got a terrible tummy ache. I suspect that was because it was moving toxins though my system. I ate some ginger and drank ALOT of water to move it out of my body. Well, the next morning I was amazed that my tummy had gotten a bit flatter!! I've been on a cleanse and doing a tON of sit ups without losing any of that belly fat, I thought it was stress or maybe I was doing something wrong, but apparently it had to do with the castor pack.
It seems important to make sure you get plenty of water and fiber while you are doing this. I'm surprised your wife was able to leave it on over night without getting a stomache ache! Thanks for posting, very helpful.