I thought it was dangerous but here's some info:
Did you also know that the average cat or dog could die after eating one to five cigarettes? Swallowing a cigarette is so dangerous that it could take no more than a few minutes to kill your pet! Signs of nicotine poisoning are: rapid breathing, vomiting, diarrhea, weakness, coma, and cardiac arrest. If you suspect that your pet has eaten a cigarette, call your veterinarian immediately--this could be a matter of life and death.
GET TO A VET NOW!