The Effects of Smoking

Cigarette smoke contains many harmful substances, including:

  • Nicotine
  • Carbon monoxide
  • Tar

Cigarette smoke also contains other toxic chemicals and carcinogens that can damage the body’s cells and tissues.

Close-up view of discarded cigarette butts, some with charred ends, amassed together. The white filters contrast with the burnt ends and amber-coloured bodies.

Harmful Substances in Cigarettes


Nicotine is an addictive chemical found in tobacco products, including cigarettes. It can lead to physical dependence, causing users to crave the substance. Nicotine can also have negative effects on cardiovascular health by increasing heart rate and making the blood vessels narrower. This increases blood pressure, which can increase the risk of developing heart disease.

Carbon monoxide

Carbon monoxide (CO) is a colourless and odourless gas that can be harmful to humans when inhaled. It replaces oxygen in the body, reducing the amount of oxygen that is available to cells and tissues.

This can lead to carbon monoxide poisoning, which can cause symptoms such as headache, dizziness, weakness, and nausea. Long-term exposure to carbon monoxide can cause more serious health problems, such as brain damage and heart disease.


The airways in the lungs are lined with tiny, hair-like structures called cilia. These cilia help move mucus, a sticky substance that traps dust, bacteria and other particles, preventing them from entering the lungs.

When a person smokes, the tar in cigarette smoke coats the cilia, damaging them and making it more difficult to remove mucus from the airways. This damage can lead to a condition known as the smoker’s cough, where the person coughs more frequently as the body tries to clear the airways.

Over time, the damage caused by smoking can lead to serious respiratory diseases such as bronchitis and emphysema.

  • Bronchitis is a disease that inflames the lining of the bronchi.
  • Emphysema is a disease that destroys the air sacs in the lungs.

Both diseases make it difficult to breathe.

Smoking can increase the risk of developing cancer in the lungs, throat, and mouth due to the presence of carcinogens in cigarette smoke.

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