Yes baby oil (mineral oil) is safe to use, but I don't know how it would effect someone with IBS
It basically gives the user diarrhea, the oil coats the colon and loosens up the bowels.
Here's a link to enemas and the results from the oil enema are the last one.
http://institute.homeip.net/Enema%20Recipes.htm
I would suggest a yogurt enema, and even better try homemade yogurt, its soothing and good for people with IBS
I see that someone already beat me to the punch anyway lol