Originally posted by Darth_Erebus
Nicotine is what makes tobacco (all forms, not just cigarettes) addictive but it's the tar that does the most damage. Tar builds up in the lungs and hampers breathing. Tar also destroys lung tissue. Tar is the black resiny substance in cigarette residue, stains, and burns.
That may be but Nicotine still is the most dangerous...very poisonous I believe to have heard and therefore know.