Ambien can have some pretty weird side effects. There are some sites that people post about certain drugs and you would be surprised how strange some of the side effects of drugs can be. It is called Askapaient. Anyway, Ambien tears my stomach up bigtime. Not painful, just very uncomfortable, feels like I have to go all the time (I don't) and if I take more than a couple days goes right into IBS like problems. I don't have the same experience with Lunesta though it gives me a little headache but doesn't last. I think the Ambien works better and more consistently but will have to stick with Lunesta. Insomnia is worse for me than IBS and like IbS no cure.