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Drugs and health
Drugs are substances that change chemical reactions in the
body. Medical drugs relieve disease and illness, and are
extensively tested before being used. Thalidomide is a drug that
caused unexpected and damaging side effects to babies in the
last century.
Recreational drugs such as alcohol and tobacco…

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and later they are trialled using human volunteers. At this point, any
potential side effects should show themselves. Most substances do not
pass all the tests and trials, so drug development is expensive and
takes a long time.
Medical drug trials are not without risk. Sometimes very severe and

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Nicotine is the addictive substance in tobacco smoke. It reaches the
brain within 20 seconds and creates a dependency so that smokers
become addicted.

Carbon monoxide
Carbon monoxide combines with the haemoglobin [haemoglobin:
the red protein found in red blood cells that transports oxygen round
the body ] in…

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A smoker's lung

The images above compare a healthy lung to a smoker's lung. Tar
deposits can be seen clearly in the smoker's lung.

The alcohol in alcoholic drinks such as wines, beer and spirits is
ethanol. It is a depressant. This means that it slows down signals in…

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heroin and cocaine are illegal recreational drugs
Many drugs alter the chemical processes in the body in such a way that
the person taking them becomes addicted to them. They feel they have
to take the drugs, and they suffer unpleasant withdrawal symptoms if
they stop taking them. All four…


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