Because they give him nightmares, Sarah is known to have lectured Jimmy on how he shouldn't eat them before bed. It is heavily implied in "The Eds are Coming" that on the night of Jimmy's nightmare about the alien invasion, he had eaten a whole box of the candies before bed. Judging by the snack's name, the Bon-Bons are probably bad for the stomach.
Each pack appears to come in a rectangular red box with pink stripes and contain a total of eight candies. From the size of the candy wrappers and the box, they appear to be large chocolate candies.