Harmful Substances

Tobacco smoke contains various harmful substances dangerous to health. With every cigarette, HTP or ENDS use, the lungs are flooded with tobacco smoke or heated aerosols. Via the bloodstream, the various substances and chemicals spread throughout the entire body.


Nicotine – along with cocaine and heroin – is regarded as one of the most addictive substances. Some studies have shown that nicotine dependence may even be heritable, transmitted from mothers or even grandmothers. Cigarettes and ENDS are particularly highly efficient nicotine delivery devices and evidence demonstrates that smokers can become addicted to smoking very quickly. Nicotine enters the blood through the lungs, crosses the blood-brain barrier and reaches the brain after nine to 19 seconds (faster than after injection into a vein).Nicotine is well known to have serious adverse effects, in addition to being highly addictive. As shown in various studies, the biological effects of nicotine are widespread and extend to all systems of the body, including the cardiovascular, respiratory, renal, and reproductive systems. Nicotine suppresses the immune response by impairing key immune system processes. The inhalation of nicotine through heated aerosols also affects pulmonary sensitivity and enhances lung inflammation, as well as lung injury. Thus there are increasing grounds to believe that, regardless of whether nicotine is consumed with cigarettes or ENDS, it plays an adverse role on pulmonary health and one may be at an increased risk for bacterial and viral infections.

Physical dependence

The effect on the brain is decisive for physical dependence. Here, nicotine predominantly promotes the release of dopamine. The breakdown of nicotine leads to withdrawal symptoms such as decreased heart rate, increased appetite or weight gain, and it causes a strong craving for the next nicotine stimulation.

Psychological Dependence

In addition to physical dependence, people also develop a psychological dependence on nicotine. A marker for nicotine addiction is the occurrence of withdrawal symptoms following cessation of its use. Typically, physical symptoms following cessation or reduction of smoking include the urge to smoke, irritability, anxiety, difficulty concentrating, restlessness, and sleep disturbances.


Tobacco smoke is a mixture of gases and solid particles. In addition to nitrogen, oxygen and carbon dioxide (harmless to health), gases include toxins such as:

  • Carbon monoxide: binds to red blood cells in the alveoli faster than oxygen. People who smoke a lot absorb up to 15 percent less oxygen. Carbon monoxide primarily causes vascular damage.
  • Hydrogen cyanide: can cause headaches, dizziness, and vomiting after short exposure.
  • Nitric oxide: irritates and damages the respiratory tract.
  • Ammonia: ammonia vapours irritate the eyes and respiratory tract even in small doses; ammonium compounds increase the addictive effect of cigarettes.
  • Formaldehyde: is carcinogenic, and the gas irritates the eyes and respiratory tract.


Tar or condensate comprises the solid particles of tobacco smoke (particles) without their water content and without nicotine. The constituents of tar mainly cause cancer. Tar mainly contains:

  • Hydrocarbons (carcinogenic)
  • Phenols (carcinogenic, irritates the mucous membranes)
  • Benzoles (carcinogenic)
  • Nitrosamines (carcinogenic)
  • Various heavy metals such as cadmium (carcinogenic, can damage the kidneys in the long term), lead (carcinogenic, can damage the brain, kidneys, nervous system and red blood cells after long exposure, endangers the foetus) and nickel (carcinogenic, irritates the respiratory tract, causes pneumonia).

Filter Cigarettes Increase Cancer Risk

Cigarettes with small air holes in the paper and a filter increase the risk of lung cancer. Smokers suck harder on filter cigarettes and draw the tobacco smoke deep into their lungs. The pollutants in tobacco smoke thus penetrate right into the tiny alveoli of the lungs.The law therefore prohibits false designations that can give the impression that one tobacco product is less harmful than others. So-called mild or light, but also filter cigarettes, have just as great an addictive effect and are just as harmful as other cigarettes.


Concerns regarding ENDS primarily focus on nicotine exposure, however recent investigations have revealed that users of ENDS are exposed to various additive substances as well, including aldehydes, fine particulate matter, metals and others. Moreover, chemical flavourings are often used that are associated with severe respiratory diseases.


2014 Surgeon General's Report: The Health Consequences of Smoking - 50 Years of Progress www.cdc.gov/tobacco/data_statistics/sgr/50th-anniversary/index.htm.

Action on Smoking and Health (2014), factsheet no:12 What's in a cigarette? www.ash.org.uk/information/facts-and-stats/essential-information.

German Cancer Research Center (2015) Nicotine as a health risk. Facts about smoking, Heidelberg www.dkfz.de/de/tabakkontrolle/Fakten_zum_Rauchen.html.

Mishra A, Chaturvedi P, Datta S, Sinukumar S, Joshi P, Garg A. Harmful effects of nicotine. Indian Journal of Medical and Paediatric Oncology : Official Journal of Indian Society of Medical & Paediatric Oncology 2015;36: 24-31.

World Health Organization. (2015). Fact sheet on ingredients in tobacco products (No. WHO/NMH/PND/15.2). World Health Organization.

Rabinoff, M., Caskey, N., Rissling, A., & Park, C. (2007). Pharmacological and chemical effects of cigarette additives. American Journal of Public Health, 97(11), 1981-1991.

Allen JG, Flanigan SS, LeBlanc M, Vallarino J, MacNaughton P, Stewart JH, et al. Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes. Environmental health perspectives 2016;124: 733-9.


Fact sheet: Tobacco smoke under the microscope

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