Poisons in a cigarette

We all know that cigarettes are terrible for our health, but what's in a cigarette that actually causes damage? We take a closer look at the toxins, poisons and harmful chemicals found in tobacco smoke.

Tobacco smoking is the leading preventable cause of disease and death in Australiai. The smoke from a cigarette causes significant damage to our bodies, both inside and out, and also causes harm to those exposed to second-hand smoke. Cancer, stroke, and heart and lung disease are just a few of the damaging consequences of smoking tobaccoii.

Cigarette smoke can contain over 4000 chemicals with at least 70 of those proven to cause cancer.

Cigarette smoke is toxic and can contain more than 4000 chemicals with at least 70 of those being known causes of canceriii,iv. This smoke is not only dangerous for smokers but also for those exposed to second-hand smoke - children are especially vulnerablev. The following chemicals are just a handful of the harmful ingredients in a cigarette.


Nicotine, which originates from the leaves of the tobacco plant, is the addictive ingredient in a cigaretteii,v. Once inhaled, nicotine runs through the bloodstream and stimulates the nervous systemvi. It releases chemicals that bring about a relaxed sensation, which the smoker becomes addicted tovii. Nicotine also gives the smoker a 'rush': it activates the production of adrenaline, which increases the heart rate and redirects blood from the extremities, such as the feet and hands, to the brain and other organsvii.

Affecting the neurotransmitters in the brain, nicotine impacts the way certain brain cells work, and makes the regular smoker become 'addicted' to the presence of nicotine in the bodyvii. A smoker consequently craves nicotine, finds it difficult to quit, and experiences withdrawal symptoms when the craving isn't satisfiedvii. Despite these factors a smoker can retrain their body to function without nicotine and eventually the cravings subsidevii.


Used for road surfaces and to preserve timberviii, tar is a chemical compound found in cigarettesii. It is a black substance made from a combination of poisonous chemicals including ammonia, toluene and acetone, which is commonly used in paint stripper and nail polish removerix. Although some of it is exhaled and coughed up, inhaled cigarette tar is primarily absorbed into the bodyv.

In the lungs, tar kills the tiny protective hairs, called cilia, which brush mucus (containing toxins and infections) from the lungs and airwaysv. Tar is the main cause of lung and throat cancer in smokersx.


Ammonia is a pungent-smelling ingredient commonly found in floor, toilet and window cleanersiii,iv,ix. It is also used in the manufacture of fertilisers and explosivesiv. In cigarettes, it aids nicotine absorption by converting the nicotine in tobacco into a gasiv. Ammonia is detrimental to the respiratory system as it kills the cilia cells, which protect the respiratory system from infectioniv.

Carbon monoxide

Carbon monoxide is a colourless and odourless gas that is usually formed through the burning of carbon-based fuelsii,iv,xi. We experience it daily from vehicle exhaust fumes and home heating appliances in small amountsiv,xi. As much as 3 to 5% of tobacco smoke is carbon monoxideiv.

This poisonous gas, once inhaled, sticks to red blood cells in the body, squandering the amount of oxygen that can be absorbed by them. In this way, carbon monoxide reduces the blood's ability to transport vital oxygen to the body's organs and tissuesiv. This results in poor circulation to the body's extremities, causing pain and - in severe cases - gangrene requiring amputationxii.

Hydrogen cyanide

Hydrogen cyanide is a deadly gas that is commonly used as an industrial pesticideiv. Hydrogen cyanide, like ammonia and carbon monoxide, also kills the cilia cells in the lungsiv. Although hydrogen cyanide does not explicitly cause cancer, it can makes it easier for other carcinogenic (cancer-causing) chemicals to infiltrate the bodyii,iv.


Used in wood preservativesiv and pesticidesxiii, arsenic is a carcinogen that also causes damage to the heart, blood vessels and DNAiv,xiv. The small amounts of arsenic ingested by a smoker remain in the body and over time accumulate to levels that cause potentially widespread damage to the bodyiv.


Cadmium is a cancer-causing metal used in the production of batteriesiv,ix. The concentration of cadmium in a smoker's blood can be twice that of a non-smokeriv. It damages the kidneys and the linings of arteries, while also preventing cells from repairing damaged DNAiv.


Formaldehyde is an odorous carcinogenic chemical commonly used to kill bacteria. It is used in mortuaries, and in paint and chemical manufacturing. Formaldehyde has been linked to several types of cancer. The air surrounding places where people smoke has up to three times the normal level of this poisonous compound presentiv.


Benzene is an industrial solvent commonly used in the manufacturing of petroliv,ix. It has been directly linked to cancer, in particular leukaemiaiv. A smoker inhales on average ten times more benzene than a non-smoker, and is therefore at greater risk of developing canceriv.


Polonium-210 is the radioactive element polonium's most common formiv. Polonium is found in tobacco smoke and is known to release alpha-radiation that damages cells in the lungs and airwaysiv,xv. Certain types of radiation, including alpha-radiation, are known to mutate DNA in cells causing the cells to become cancerous or diexv. Smokers are exposed to significantly more radiation daily than a non-smokeriv. One report estimates that a person who smokes 20 cigarettes per day experiences the same level of radiation as 300 chest x-rays a yearxvi.

Additives such as honey, cinnamon and vanilla are used to alter the smell and taste of cigarettes.

Nitrogen oxide

Nitrogen oxide is a noxious gasiv. The human body naturally produces small amounts of nitrogen oxyide. However, the additional nitrogen oxide from smoking further expands the smoker's airways. This enables more of the chemicals in a cigarette to be absorbed. When not smoking, nitrogen oxide can reduce the smoker's internal nitrogen oxide production line, constricting the airways. This can make it more difficult for a smoker to breathiv.

Additives to tobacco

Chemicals in tobacco and additives to cigarettes make smoking a harmful habit. Aromatic scents such as menthol, honey and vanilla are used to mask the natural smell and taste of cigarette smoke to make smoking less abrasive for smokers and less invasive for non-smokersxvii.

Over a lifetime, the thousands of chemicals inhaled through smoking cigarettes damage vital organs and tissues, and poison the smoker slowly. The sooner you quit smoking the sooner you can get back your life, free yourself from addiction, and take advantage of the health and monetary benefits of quitting.

iAustralian Government 2012, Smoking – a leading cause of death, viewed 29 August 2013,

iiBetter Health Channel 2013, Smoking – effects on your body, viewed 8 August 2013,

sup>iiiAustralian Government 2012, Cigarettes and poison, viewed 8 August 2013,

ivCancer Research UK 2012, Smoking and cancer: What's in a cigarette?, viewed 8 August 2013,

vNSW Government 2007, Nicotine and other poisons, fact sheet, viewed 8 August 2013,

viNational Institute on Drug Abuse 2013, The Brain's Response to Nicotine, viewed 10 September 2013,

viiQuit Tobacco 2011, Effects of Nicotine, viewed 28 August 2013,

viii'Tar', Oxford English dictionary online, viewed 10 September 2013,

ixOxyGen, What's in cigarette smoke?, viewed 8 August 2013,

xAustralian Government 2012, Tar information sheet, viewed 10 September 2013,

xiMinnesota Department of Health, Carbon Monoxide (CO) Poisoning in Your Home, viewed 8 August 2013,

xiiBetter Health Channel 2013, Smoking and heart disease, viewed 10 September 2013,

xiii'Arsenic', Oxford English dictionary online, viewed 8 August 2013,

xiv'High arsenic levels in rice linked to DNA damage' 2013, ABC Science, 23 July, viewed 8 August 2013,

xvAmerican Cancer Society 2010, Radiation Exposure and Cancer, viewed 28 August 2013,

xviZaga V, Gattavecchia E 2008, 'Polonium: the radioactive killer from tobacco smoke', Pneumologia, Oct-Dec;57(4):249-54, viewed 28 August 2013,

xviiCancer Research UK 2009, Additives in cigarettes, viewed 8 August 2013,