They are sweet, small and easy to eat by the handful. Before you indulge, though, know this. Fans of the treat are reporting some unpleasant side effects!

The cause...Haribo Sugarless Gummy Bears.

The effect...gastric distress comparable to taking "100 Ex-lax tablets."

Fans of sugarfree candy have gone on-line to share their symptoms, and the general consensus is that just 15-20 of these innocent looking gummies will have you quickly screaming towards the nearest restroom.

The reason for the gastric distress most likely is the artificial sweetener Lycasin, made from maltitol. It falls into the same category as sorbitol and xylitol, both of which are commonly found in sugarless gum.

Haribo does acknowledge that "this product may cause intestinal distress if eaten in excess."

Consider yourself warned! Go easy on those sugarless gummy bears. They aren't as innocent as they look.