I made the same mistake with the sugar free Jelly Belly's.
I had already learned that sugar alcohols (any sweetener ending in 'ol) can have this effect, so I already knew to read the label and to never exceed the recommended serving size.
When I got sick, I realized that I had made a mistake I knew not to make, but even so I was shocked when I read the label. The serving size listed was four jelly beans. Who the heck ever eats only four jelly beans?
It did reinforce to me the importance of reading serving sizes, especially on foods sweetened with sugar alcohols.
Usually I don't have a problem if I don't exceed the recommended serving size. Although if I'm having a problem with constipation, a serving or serving and a half can be helpful.