Registered Nurses' Association of Ontario

Harmful Substances in Tobacco

  • Tobacco smoke contains more than 7,000 chemicals. Hundreds of these chemicals are toxic and at least 69 are known carcinogens.
  • Nicotine is the addictive component in tobacco leaves.  Nicotine activates nicotinic acetylcholine receptors in the brain associated with a variety of subtle effects that perpetuate its use.
  • Nicotine causes a range of side effects, such as a lowered appetite; elevated mood, heart rate, and blood pressure; nausea; and diarrhea. However, individuals who regularly use nicotine can develop a tolerance to its effects.
  • Sudden cessation, either voluntarily or involuntarily, is accompanied by withdrawal that can begin within hours of the last use. Withdrawal symptoms from nicotine may include strong cravings; mood changes, such as anxiety and depression; restlessness; insomnia; increased appetite; and lack of mental focus.
  • Strong evidence demonstrates that tobacco interventions can reduce health-care costs and increase quality of life for those who quit or reduce their use.
  • For more information on the harms associated from tobacco use click here.
  • For more information on the benefits of quitting smoking click here
Addiction and Mental Health
Integrating Tobacco Interventions into Daily Practice
Background Information