What’s in a cigarette?

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  • Over 5,000 different chemicals are released when a cigarette burns
  • Many of these chemicals are poisonous and have been found to cause cancer

A cigarette is much more than tobacco wrapped in paper. The cocktail of chemicals in cigarette smoke comes from different sources when a cigarette is made and used.

Some chemicals are found naturally in the tobacco plant, such as addictive nicotine, and some are absorbed by the plant from the soil, air or fertilisers.

Some are added when tobacco leaves are processed. Others form when a cigarette burns, so are only in the smoke coming off a cigarette.

Roll-up tobacco cigarettes contain the same cancer-causing chemicals as manufactured cigarettes, so aren’t any safer.

Tobacco-specific nitrosamines are a group of cancer-causing chemicals only found in tobacco. But many of the cancer-causing chemicals in tobacco and cigarette smoke have other surprising uses.

This infographic has more information

Find out more about how these chemicals can cause cancer on this page.

What is nicotine and why do people smoke?

Nicotine is a highly addictive drug. Most people do not smoke regularly out of choice alone, but because they are addicted to nicotine. But using nicotine itself, for example in nicotine replacement therapy, doesn’t cause cancer.

People may associate smoking with feeling less stressed and anxious, but this is only because it temporarily relieves the unpleasant symptoms of nicotine withdrawal.

People who smoke can also make connections with situations when they usually smoke, like having a cigarette whilst reading the newspaper, it can just be a habit. This can reinforce the addiction to smoking.

That is why stopping can be difficult, but it is possible. In recent years the number of people who smoke cigarettes in the UK has fallen.

Find out more about how to stop smoking here.

  • Tobacco can be used in many different forms – but all are linked to cancer
  • There is no safe way to use tobacco and there is support available to help you stop

The sweet flavourings in shisha may make people believe it is harmless, but this is not the case. Shisha contains tobacco, and smokers inhale cancer-causing chemicals and addictive nicotine.

Smoking shisha could at least double your risk of lung cancer and may be linked to some other cancer types, like mouth and stomach cancers.

Unlike cigarettes, shisha is burnt using charcoal so users can also be exposed to dangerously high levels of the poisonous gas carbon monoxide.

Cigars, pipes or bidis increase the risk of many cancer types including lung, mouth and upper throat, food pipe (oesophagus), voice box (larynx) and stomach. Smoking tobacco in these ways is just as bad for you as smoking cigarettes.

Action on Smoking and Health. What’s in a cigarette (2014).

International Agency for Research on Cancer. Tobacco smoke and involuntary smoking. Vol 83, 1–1413 (2004).

International Agency for Reseach on Cancer. Personal Habit and Indoor Combustion: Tobacco Smoking. Vol  100 E, 377–504 (2012). https://www.ncbi.nlm.nih.gov/books/NBK304395/

International Agency for Research on Cancer. Smokeless Tobacco and Some Tobacco-specific N -Nitrosamines. Vol 89 (2007).

Smith, C. J. et al. IARC carcinogens reported in cigarette mainstream smoke and their calculated log  P values. Food Chem. Toxicol. 41, 807–817 (2003).

The Tobacco Advisory Group of the Royal College of Physicians. Nicotine Addition in Britain (2000).

The Royal College of Physicians. Nicotine without smoke: Tobacco harm reduction (2016).

Waziry, R., et al. The effects of waterpipe tobacco smoking on health outcomes: an updated systematic review and meta-analysis. Int. J. Epidemiol. 46, 32–43 (2017).


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