What is in tobacco?

Cigarettes, cigars, and spit and pipe tobacco are made from dried tobacco leaves, as well as ingredients added for flavor and other reasons. More than 4,000 different chemicals have been found in tobacco and tobacco smoke. Among these are more than 60 chemicals that are known to cause cancer (carcinogens).

Many substances are added to cigarettes by manufacturers to enhance the flavor or to make smoking more pleasant. Some of the compounds found in tobacco smoke include ammonia, tar, and carbon monoxide. Exactly what effects these substances have on the cigarette smoker's health is unknown, but there is no evidence that lowering the tar content of a cigarette lowers the health risk.

As of now, cigarette manufacturers are not required to give out information to the public about the additives used in cigarettes, which has made it harder to determine their possible health risks. But with the passage of a new federal law, manufacturers must submit lists of ingredients to the Food and Drug Administration (FDA) starting in 2010. The FDA will make lists of harmful ingredients available to the public by or before June 2013.
Nicotine addiction

Addiction is marked by the repeated, compulsive seeking or use of a substance despite its harmful effects and unwanted consequences. Addiction is defined as physical and psychological (mental and emotional) dependence on the substance. Nicotine is the addictive drug in tobacco. Regular use of tobacco products leads to addiction in many users.

In 1988, the US Surgeon General concluded the following:

Cigarettes and other forms of tobacco are addicting.

Nicotine is the addicting drug in tobacco.

The ways people become addicted to tobacco are much like those that lead to addiction to other drugs such as heroin and cocaine.

These statements are as true today as they were then. All forms of tobacco have a lot of nicotine. It is easily absorbed through the lungs with smoking and through the mouth or nose with oral tobacco (spit, snuff, or smokeless tobacco). From these entry points, nicotine quickly spreads throughout the body.

Tobacco companies are required by law to report nicotine levels in cigarettes to the Federal Trade Commission (FTC). But in most states they are not required to show the amount of nicotine on the cigarette package label. The actual amount of nicotine available to the smoker in a given brand of cigarettes is often different from the level reported to the FTC. In one regular cigarette, the average amount of nicotine the smoker gets ranges between about 1 mg and 2 mg. But the cigarette itself contains more nicotine than this. The amount people actually take in depends on how they smoke, how many puffs they take, how deeply they inhale, and other factors.
How powerful is nicotine addiction?

About 70% of smokers say they want to quit and about 40% try to quit each year, but only 4% to 7% succeed without help. This is because smokers not only become physically addicted to nicotine; there is a strong emotional (psychological) aspect and they often link smoking with many social activities. All of these factors make smoking a hard habit to break.