Cigarette Side Effects: What Smoking Does to Your Body

Cigarette Side Effects: Short-Term and Long-Term Harm

Last reviewed: November 10, 2026Next review due: November 2027

Key takeaways

Health Canada links smoking to more than two dozen diseases and conditions, including cancer and heart disease. Smoking causes 85% of new lung cancer cases in Canada and raises the risk of gum disease by 85%. It also stains teeth and nails, ages skin and slows wound healing. Most of the risks start to reverse after you quit.

A cigarette burns more than tobacco. Health Canada states that tobacco smoke contains over 7000 chemicals, of which over 70 are known to cause cancer. The effects below come from that exposure, and from nicotine, which is the addictive part and keeps people smoking long enough for the damage to add up.

Effects you can see

Health Canada’s pages on the visible consequences of smoking and on oral disease describe four.

Skin. Chemicals in cigarettes can reduce the flow of blood to the skin, making it more prone to premature aging, wrinkling and psoriasis. They can also stain fingers and nails yellow.
Teeth. The chemicals in tobacco smoke can stain teeth. Smoking promotes the growth of harmful bacteria on tooth surfaces, and nicotine hinders the repair of damaged gum tissue.
Gums. Someone who smokes increases their risk of gum disease by 85% compared with people who do not smoke.
Healing. Smoking suppresses the immune system, which reduces the body’s ability to heal sores and other wounds.

Quitting reverses part of this. Health Canada says quitting can improve the health of skin, improve its colour and smoothness, and protect it from premature aging.

Effects on the lungs

Health Canada describes COPD, the group of lung diseases that includes emphysema and chronic bronchitis, as causing frequent coughing and excess phlegm, with shortness of breath during everyday activities as the main symptom. See smoker’s lungs versus healthy lungs and smoker’s cough for the mechanics and when to get checked.

For lung cancer, the department says smoking accounts for 85% of all new cases in Canada.

Effects on the heart and blood vessels

Cardiovascular diseases caused by smoking include heart attacks and angina, blockages in the legs (peripheral vascular disease) and strokes.

Other effects

Health Canada’s broader risk list for people who smoke covers problems with the heart and blood vessels, certain cancers, lung and respiratory problems, other health issues and premature death. For women it adds problems getting pregnant (fertility problems) and cancer of the cervix. The page says smoking is linked to more than two dozen diseases and conditions in all.

On deaths, Health Canada states that based on 2017 data about 48,000 people in Canada die from tobacco use each year, and a later estimate is about 46,000 deaths in 2020.

What changes when you stop

Most of these risks start to reverse after you quit, and some benefits begin in a matter of hours, according to Health Canada. Life expectancy improves. For time points such as one year or ten years, use the quitting timeline.

Smoke harms people nearby too; see health effects of second-hand smoke.

Health information is general and educational. It does not replace advice from a doctor, pharmacist or nurse. Read the full disclaimer.

Frequently asked questions

What are the main side effects of smoking cigarettes?

Health Canada lists risks to the heart and blood vessels, certain cancers, lung and respiratory problems, premature death and, for women, fertility problems. It also describes visible effects: stained teeth and nails, skin that ages and wrinkles faster, and slower wound healing.

How much does smoking raise the risk of gum disease?

Health Canada says someone who smokes increases their risk of gum disease by 85% compared with people who do not smoke.

Do the effects reverse if you stop?

Health Canada says most of the risks start to reverse after you quit, and that some benefits begin in a matter of hours. Tooth loss risk matches that of someone who has never smoked after 13 or more years without smoking.