Which are the most dangerous substances in tobacco?

Cigarettes contain over 4000 chemicals, around 50 of which are known to be carcinogens (chemicals that increase the risk of cancer). The main substances in tobacco smoke are nicotine, carbon monoxide and tar, along with many other toxic chemicals.

• Nicotine is a powerful, fast-acting stimulant and is what makes smoking addictive. It increases your heart rate and blood pressure, affects your mood and behaviour, and speeds up your metabolism.
• Nicotine addiction results from the brain releasing a chemical associated with feelings of
• well-being.
• Carbon monoxide is a poisonous gas found in car exhaust fumes and produced by faulty gas appliances. It replaces the oxygen in the blood. This stops the cells and tissues from getting the oxygen they need to work properly.
• Tar is the sticky brown substance that stains smokers’ fingers and teeth. Approximately 70% of the tar in cigarette smoke stays in the lungs. The tar is responsible for most of the damage to the lungs.