There can be up to 600 additives and flavourings in a single cigarette.
There are over 4,000 chemicals in tobacco smoke, many of which are poisonous, 43 of which have been proven to be carcinogenic (causing cancer). These chemicals include:
Nicotine: Nicotine is the main addictive ingredient in tobacco. The strength of addiction is said to be as powerful, or more so, than that of heroin. Nicotine is readily absorbed into the blood and gives a hit (a rush) to the brain in about 10 seconds. It is the regular hits of nicotine that the brain comes to expect and when people quit it causes withdrawal symptoms. Nicotine is a stimulant that increases the heart rate and blood pressure. Nicotine is a poison - swallowing one drop of pure nicotine can kill an adult.
Tar: When a cigarette burns, tar is released and deposited into the lungs every time a person inhales. Smoking 20 or more cigarettes a day deposits 450gm to 650gm into the lungs every year. Tar is the main cause of lung and throat cancer in smokers.
Carbon Monoxide: This is the same chemical pushed out by cars. Carbon monoxide is a colourless, odourless and very toxic gas, which is taken up more readily by the lungs than oxygen. It prevents the blood carrying oxygen around the body. A heavy smoker's ability to carry oxygen around the body is reduced by up to 15%. High levels of carbon monoxide in the blood is typical of smokers and, together with nicotine, increases the risk of heart disease, hardening of the arteries and other circulatory problems.
Acetone: Acetone is used as a solvent to remove nail varnish.
Ammonia: Ammonia speeds up the delivery of the nicotine. It freebases the nicotine in the same way as a crack user takes cocaine.
Hydrogen cyanide: Another gas that reduces the body's ability to carry oxygen around the body.
Benzene: Used as a solvent in fuel and dyes. Known to cause cancer.
Cadmium: Used to make batteries, cadmium is known to cause kidney damage. It increases the risk of developing lung cancer.
Pyridine: Pyridine is a central nervous system depressant that boosts the effect of smoking.