All about smoking

A cigarette is the only consumer product which, when consumed as intended, kills half of its regular 
consumers. This information sheet explains the physical and biological aspects of tobacco smoking.  
In particular it focuses on: what’s in a cigarette, the role of addiction in smoking and the physical 
effects of just one cigarette. 


What’s in a cigarette? 



Tobacco is the main ingredient in cigarettes. A 
manufactured cigarette is made up of two main 
types. 
•  Cured types  - flue cured, light and dark air 
cured, sun cured 
•  Reconstituted (stems, ribs etc) and expanded 
tobacco. Both of these lead to cheaper 
cigarettes by using less tobacco. 
Cigarette additives 
Cigarette manufacturers have spent many years 
manipulating what goes into cigarettes by using 
additives.  
Additive types include  
•  Humectants  - up to 5% of the weight of a 
cigarette. These preserve moisture, as dry 
tobacco has harsh taste. Glycerol and 
propylene glycol are most commonly used. 
•  Flavour - added to counteract reductions in 
flavour due to filters and the use of 
reconstituted tobacco. Natural and synthetic 
flavour enhancers are used to give woody, spicy, minty, fruity, sweet and flowery

flavours.  Flavours also mask the ‘harshness’ 
of smoking, and may help young smokers 
begin and continue smoking. 
Others, such as menthol, numb a smoker’s 
throat. Ammonia raises smoke pH, enabling 
more nicotine to be absorbed.


Nicotine, a poisonous substance  



Nicotine is the drug in tobacco, which causes 
addiction among smokers. It is a highly toxic 
chemical, and is often used in industrial 
pesticides. It is regulated in all circumstances 
apart from in cigarettes.  
Smokers inhale a very small dose of nicotine, and 
are not at risk of nicotine poisoning. However, 
children who eat or swallow cigarettes or butts 
should receive medical attention immediately. 

Nicotine has a number of direct effects on the 
body. It stimulates the sympathetic nervous 
system, increases the heart rate and blood 
pressure, and causes constriction of the small 
blood vessels under the skin.  
Carbon monoxide (CO) 
Carbon monoxide (CO) is an odourless, tasteless 
gas, giving no warning of its presence in most 
circumstances. In large amounts it is rapidly fatal. 
CO is strongly linked with the development of 
coronary heart disease. CO is formed when a 
cigarette is lit. 
Tar 
This is the term used to describe the mixture that 
is formed from the tiny particles in cigarette 
smoke. All cigarettes contain tar, even 'light' or 
mild cigarettes.   
Tar is made up of lots of chemicals - mainly 
nitrogen, oxygen, hydrogen, carbon dioxide, and 
carbon monoxide as well as numerous organic 
chemical compounds.  Also found in tar are 
carcinogenic compounds - chemicals that may 
trigger cancer - such as nitrosamines and 
polycyclic aromatic hydrocarbons. 
Other chemicals 
Tobacco smoke contains many chemicals, some of 
which are poisonous and others that cause 
cancer.  
Many of the chemicals in tobacco smoke cause 
cancer when painted on the skin of laboratory 
animals such as rats and mice. In smokers, 
chemicals in tobacco smoke may damage genetic 
material in cells. Smokers absorb these 
carcinogenic chemicals through their lungs, 
contributing to cancer in lungs and other parts of 
the body such as the bladder, kidney and 
pancreas. 
Tobacco smoke contains chemicals such as 
hydrogen cyanide, ammonia, nitrogen dioxide, 
acrolein, and formaldehyde. These chemicals 
paralyse the cilia (tiny hair-like processors on the 
cells lining the airways), which clear mucus and 
anything that deposits on them. Smokers' lungs 
are more sensitive to cancer-causing chemicals 
because their cilia do not clear the airways 
effectively. 



Tobacco and addiction 
Most smokers have been aware that tobacco 
smoking is addictive for a long time. The US 
Surgeon General's 1988 report reached three key 
conclusions about dependence and tobacco. 
•  Cigarettes and other forms of tobacco are 
addictive. 
•  Nicotine is the drug in tobacco that causes 
addiction. 
•  The pharmacological and behavioural 
processes that lead to tobacco addiction are 
similar to those leading to addiction to other 
drugs, such as heroin and cocaine. 
We now know that since the 1960s, tobacco 
companies knew that people continue to smoke 
because they are addicted to nicotine.   
As a lawyer acting for Brown & Williamson said: 
Nicotine is addictive. We are, then, in the 
business of selling nicotine, an addictive drug.
But in public discussion, tobacco companies 
continued to deny that nicotine was addictive.  In 
the last few years, some tobacco companies have 
agreed that smoking is addictive. But to try and 
confuse people, some have compared smoking’s 
addictiveness to being addicted to shopping or 
eating chocolate.  
Almost all smokers are addicted to nicotine. Very 
few do not smoke daily. We only have a limited 
understanding of the underlying factors that 
contribute to nicotine addiction, but it is likely 
that genetic, as well as environmental factors play
a part. 
It is estimated that in most people, addiction 
emerges by the time they have smoked 100 
cigarettes. Trying to quit leads to a number of 
physical withdrawal symptoms, such as mood and 
performance changes, craving, irritability, 
tension, difficulty concentrating, insomnia and 
weight gain.



What happens when you smoke? 
Even one cigarette quickly causes noticeable 
physical effects on a smoker's body. When a 
smoker inhales, the nicotine contained in the 
inhaled smoke reaches the brain via the 
bloodstream in a matter of seconds. It also 
quickly reaches muscle tissue. Nicotine receptors 
(clusters of cells that react specifically to nicotine) 
in the brain and muscles quickly recognise its 
presence and a range of physical reactions take 
place, including the following: 
•  An increase in the heart rate (measured by 
your pulse rate)  
•  An increase in blood pressure, causing small 
blood vessels to narrow, and slowing of 
circulation, which is particularly noticeable in 
the hands and feet. Because of these things, 
skin temperature is also lowered. 
•  An increase in tension in some muscles. This 
can be measured by testing hand tremors 
with a tremor-testing machine before and 
after a cigarette. Strangely, nicotine can also 
relax some skeletal muscles at the same 
time. 
•  An increase in stomach secretions and 
changes brain activity. 
•  The nicotine 'hits' the brain cell receptors and 
stimulates the release of many different 
neurotransmitters - the brain's chemical 
messengers. Some of the more important 
messengers involved in nicotine's actions on 
the brain are dopamine, acetylcholine and 
serotonin. The release of these messengers 
affect how people pay attention, think, eat, 
deal with stress and feel pleasure. 
New smokers generally feel the unpleasant side 
effects of nicotine, such as headaches or 
dizziness. But after a while their bodies get used 
to it, and these effects are no longer felt. Once 
you have been smoking for a while, your body 
becomes used to a certain level of nicotine, and 
without it, you no longer feel quite 'right'.  
As the effects of the nicotine wear off, you start 
to feel uncomfortable, uneasy and 'needing a 
cigarette' - these are the beginnings of 
withdrawal symptoms as your level of nicotine 
drops. To keep up your nicotine levels, you need 
to continually dose yourself by smoking. 
Smokers go through a continual cycle of nicotine 
hit, followed by withdrawal, which prompts 
another hit - and this happens many times a day. 
They also develop a tolerance to nicotine over 
time, which means that they need to smoke more 
to get the same effect. 
The chemicals in inhaled cigarette smoke are also 
absorbed into the bloodstream. These chemicals 
are also absorbed when passive smoking, and by 
the unborn children of pregnant women. 



Carbon monoxide (CO) 
CO is formed when a cigarette is lit. It has a 
number of toxic effects on the body, the most 
important of which is that it reduces the amount 
of oxygen that is carried in the bloodstream of 
smokers. CO binds with the haemoglobin in the 
blood instead of oxygen, meaning that less 
oxygen is available to body organs and tissue. 
The heart has to pump harder to make sure that 
enough oxygen can get to all organs. 
In pregnant women, the unborn baby also has 
less oxygen available to it through the umbilical 
cord. Lack of oxygen also affects muscle 
performance.  
Generally speaking, smokers of all ages become 
short of breath and exhausted more quickly than 
non-smokers of similar age and fitness. 
Tar 
Every time cigarette smoke is inhaled, tar goes 
into the lungs. Some is breathed out, but much 
condenses deep inside the airways of the lungs.  
Coughing is the body’s way of trying to get rid of 
this tar, but chemicals in tobacco smoke paralyse 
the cilia (tiny hairs whose job it is to sweep 
foreign material out of the airways). 
Tar is a sticky brown substance, the same one 
that causes smokers' fingers to go brown, and 
teeth to stain yellow. It also causes throat and 
lung cancer. 
‘Light’ and ‘Mild’ 
Many cigarette brands use the words 'light' and 
'mild' as part of their name. These cigarettes may 
have lower tar and nicotine readings displayed on 
the pack, but the tar and nicotine yield of these 
brands when smoked is actually much higher. 
These same words may also relate to taste in a 
smoker's mind. 'Mild' tasting cigarettes have often
had flavourings and other chemicals added to the 
cigarette to mask the taste. It is of concern that 
these cigarettes may be more appealing to 
children and young people, because of additives 
such as sugar, honey, cocoa etc. 
What is clear from research is that ‘light’ and 
‘mild’ cigarettes are no better for you than any 
other brand. The switch, particularly by women, 
to 'light' and 'mild' cigarettes may go some way 
to explaining and increase in the type of lung 
cancer that is found deeper in the lungs. 
Marketing of ‘light’ and ‘mild’ 
For decades, Cigarette companies have marketed 
‘light’ and ‘mild’ cigarettes as a less harmful, less 
addictive product. These cigarettes are designed 
to deliver less tar and nicotine, even though they 
contain the same tobacco as is used in fullstrength cigarettes. Cigarette manufacturers

manipulate nicotine and tar yield in their 
cigarettes mainly by inserting ventilation holes
in the filter.  
•  The tar, nicotine and carbon monoxide (CO) 
levels of Australian cigarette brands is 
monitored by machine testing in a laboratory 
- giving rise to the numbers on the packet. 
These 'smoking machines' take puffs of 
cigarettes and measure nicotine intake and 
tar and CO output. 
•  When the machine smokes these cigarettes, 
all the holes are clear, and air is drawn in as 
the cigarette is smoked, which affects the 
readings given by the machine. 
•  When smokers smoke these same cigarettes, 
they usually cover up the holes with their 
fingers - they usually don't know they're 
there, or what they do. When these holes are 
blocked, the tar and nicotine yields from 
these 'low tar' cigarettes increases. Smokers 
will also inhale more deeply and more 
frequently in order to compensate and ensure 
they inhale enough smoke to achieve 
satisfactory nicotine 'hits'.