Sugar alcohols are laxative. Some people are very sensitive to this effect. Sorbitol is actually used medically for constipation.
Some people get loose on just sugarless gum! Look for words ending in ---ol as most of the sugar alcohols end in --ol

Some products will include a disclaimer on the package. But I have only seen that once, on a nutrition bar box. (may cause laxative effects). Mostly these are hidden and never mentioned in the ingredients as laxative. Hershey's is good at this.
They put sorbitol in some of their chocolates (the non-diabetic products) to improve texture and moistness. Russell Stover and Whitman's also have it in their regular chocolates. I would guess maybe the falling consumer use of the latter may be contributing to their selling off their company recently? (I sometimes buy the holiday tins on the after holiday sale tables, to use for my art supplies and brushes). Their tins are wonderful for this purpose...beautiful and artistic. But in the past 2 yrs the candy itself made me ill! When I read the fine print on the tins' ingredients= sorbitol was there.

Hershey's has also a new emulsifier added instead of cocoa butter, called PRPG which is also laxative for me.
http://en.wikipedia.org/wiki/Polygly...olyricinoleate
I don't trust this ingredient at all!