Health effects

How does smoking harm us and what’s in a cigarette?

Health effects

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How smoking harms and kills us

Tobacco use and breathing in other people’s smoke (second-hand smoke) causes about 5,000 deaths every year through cancer, stroke and heart disease.2 It is the leading cause of preventable death and disease in New Zealand.3 To reduce your risk, you need to stop smoking completely, not just cut back. This is because people who are cutting back on the smokes draw harder on the cigarette and breathe in even more of the harmful chemicals.

If you smoke tobacco, odds are, you WILL be affected by it. Up to two-thirds of people who smoke today and continue smoking will eventually be killed by tobacco.4 Long-term smokers will die an average of 10 to 15 years early because of smoking.5

There are five times the number of deaths from tobacco use each year, than from drowning, suicide and motor vehicle accidents combined.

Activity Number of deaths
Drowning 906
Suicide 6237
Motor vehicle accidents 3188
Tobacco–related deaths 50009
The health consequences of smoking include10
  • Smoking causes one in four cancer deaths in New Zealand.
  • It is a major cause of blindness, with about 1,300 people in New Zealand having untreatable blindness due to current and past smoking.11
  • If you are pregnant, inhaled smoke is a poison that enters your bloodstream and passes through the placenta to the baby. These poisons harm your baby’s health.12
  • Smoking increases the risk of developing cancers of the lung, oral cavity, pharynx, larynx, oesophagus, pancreas, cervix, colon and rectum (colorectal), stomach and bladder.
  • Smoking increases the risk of developing diseases of the urinary tract, pelvis, bladder and digestive tract.
  • Forty percent of all strokes in people aged under 65 years are caused by smoking.
  • Forty percent of heart disease in those under 65 is caused by smoking.
  • Smokers have two-to-three times the risk of having a sudden cardiac death (when the heart suddenly stops beating) than non-smokers.

What is smoking doing to your body?

This interactive tool shows you exactly how smoking harms the body. 

What’s in a cigarette? 13, 14

Carbon monoxide is a poisonous gas that is found in car exhaust fumes.
  • There are about 4000 chemicals in tobacco smoke, and more than 70 of those have been found to cause cancer. 15
  • Tobacco contains nicotine, a very addictive drug that goes almost directly to the brain when smoked.
  • When smoked, tobacco produces tar – a sticky brown substance that is inhaled in tobacco smoke and stains fingers, teeth and lungs.
  • Tobacco gives off carbon monoxide when smoked. Carbon monoxide is a poisonous gas that is found in car exhaust fumes.
  • The tobacco industry puts additives with its tobacco, making the tobacco more attractive, more addictive and more toxic. Sweet additives like liquorice or chocolate make cigarettes more attractive to young people.16
  • Ingredients such as menthol numb the throat so the smoker cannot feel the smoke’s aggravating effects; cocoa dilates the airways making it easier for the smoke to be inhaled.

What's in a cigarette?

Learn about all the nasties that exist in a cigarette - it may put you off smoking for good.

How nicotine works

Nicotine is the chemical in tobacco and tobacco smoke that is addictive. Some people can get addicted to nicotine after smoking just a few cigarettes. Nicotine is as addictive as drugs like heroin or cocaine. That’s why it can be so hard to stop smoking.17

Some people get addicted to nicotine after smoking just few cigarettes.

When a cigarette is smoked, nicotine is breathed in as part of the smoke from the burning tobacco. Nicotine itself does not have a significant impact on the health of people who smoke. It is the burning of tobacco that causes most of the harm.

When nicotine is breathed in from a cigarette it goes to the brain very quickly, where it increases chemicals that affect your mood, appetite and memory.  Nicotine raises your heart rate and blood pressure, slows circulation and causes rapid, shallow breathing. Nicotine also activates areas of the brain that are involved in producing feelings of pleasure and reward.18

Once someone is addicted to nicotine, they can feel a range of symptoms if they don’t smoke like irritability, nausea, headaches, and anxiety. By smoking, often people feel better again and less stressed, but nicotine is keeping you in a cycle of withdrawal that is continually acting on your brain and body which keeps you chained to the smoking habit.

When people are quitting smoking sometimes they choose to use Nicotine Replacement Therapy, or switch to vaping as a way to quit smoking, as both of these methods provide nicotine during the quitting journey.  Learn more about vaping and nicotine at

Page last updated: 13 Oct 2022