So you think you are smoking tobacco? About 4,000 chemical compounds are produced when tobacco burns. Here are some of the ones thought to be particularly harmful. (Here is a link to a list of 599 known chemicals added to cigarette tobacco http://en.wikipedia.org/wiki/List_of_additives_in_cigarettes )

• acetaldehyde
• acetone
• acetonitrile
• acrolein
• acrylonitrile
• alcohols *
• ammonia
• amphenols
• arsenic
• benza(a)anthracent
• benzene
• benzo (a)
• benzo (j)
• benzo (g,h,i)
• butylamine
• cadmium compounds
• carbon dioxide
• carbon monoxide
• catechol
• creolsother acids
• dibenz (a,j) acridine
• dibenz (a,h) acridine
• dibenzo (c,g) carbaxole
• diethylnitrosamine
• dimethylamine
• dimethylnitrosamine
• endrine
• ethylmethylnitrosamine
• fluoranthene
• formaldehyde
• furfural
• hydrazinehydrocyanic acid
• hydrogen cyanide
• insecticides
• naphthalenes
• nickel compounds
• nicotine
• nitric oxide
• nitriles
• nitrogen oxides
• N-nitrosonornicotine
• nitrosopyrolidine
• polonium-210
• pyrene
• vinyl chloride
• 1- methylindoles
• 4 & 4 methylcatechols
• 5 - mehthylchrysene
• 9 - mehthylcarbazoles

Cigarette smoke stimulates at least two different parts of the brain at the same time. It stimulates the production of cortisol, the "stress hormone," which leads to large releases of adrenaline, epinephrine, and other "rage" and "fight-or-flight" hormones and neurotransmitters, and, in the high doses that a smoker inhales, also stimulates the production of endorphins, the naturally-occurring opiates of the brain which produce the "high" smokers experience (along with the cortisol stimulation).

* Alcohol is one of the substances created upon the ignition of tobacco.