Never had cigars make me sick. Probably from years of chewing tobacco.
Heck I have been known to chew the butts of my cigars (after clipping the ash)
Not exactly good protocol, I admit
That said, only time I ever got really messed up is when iIhad placed about 4 apple slices in with my Beechnut one summer.
Don't know if it was the heat, or the new bag i had made (I would wrap ziplock bags with duct tape because they could take the abuse of being on FTX better than the regular pouches) but I got sicker than a dog off it after day 4.