Almost everybody knows that smoking is bad for the health. Images of blackened lungs line school hallways and hospital waiting rooms, but despite this people continue to take up smoking. This may have to do with the pervasive romantic image of smoking -- an image that has nothing in common with reality.

There are many ways to take tobacco. You can chew it, inhale it through the nose, and smoke it in the form of cigars or cigarettes. No matter how it's taken it is dangerous, but because smoking is the most popular way to consume tobacco it has also received the greatest attention from the medical field and the media.

When a smoker inhales a puff of cigarette smoke the large surface area of the lungs allows nicotine to pass into the blood stream almost immediately. It is this nicotine "hit" that smokers crave, but there is a lot more to smoke than just nicotine. In fact, there are more than 4000 chemical substances that make up cigarette smoke and many of them are toxic.

Cigarette smoke is composed of 43 carcinogenic substances and more than 400 other toxins that can also be found in wood varnish, nail polish remover, and rat poison. All of these substances accumulate in the body and can cause serious problems to the heart and lungs.

Cancer is the most common disease associated with smoking. Smoking is the cause of 90% of lung cancer cases and is related to 30% of all cancer fatalities. Other smoking-related cancers include cancers of the mouth, pancreas, urinary bladder, kidney, stomach, esophagus, and larynx.

Besides cancer, smoking is also related to several other diseases of the lungs. Emphysema and bronchitis can be fatal and 75% of all deaths from these diseases are linked to smoking.

Smokers have shorter lives than non-smokers. On average, smoking takes 15 years off your life span. This can be explained by the high rate of exposure to toxic substances which are found in cigarette smoke.

Smokers also put others at risk. The dangers of breathing in second-hand smoke are well known. Smokers harm their loved ones by exposing them to the smoke they exhale. All sorts of health problems are related to breathing in second-hand smoke. Children are especially susceptible to the dangers of second-hand smoke because their internal organs are still developing. Children exposed to second-hand smoke are more vulnerable to asthma, sudden infant death syndrome, bronchitis, pneumonia, and ear infections.

Smoking can also be dangerous for unborn children. Mothers who smoke are more likely to suffer from miscarriages, bleeding and nausea, and babies of smoking mothers have reduced birth weights or may be premature. These babies are more susceptible to sudden infant death syndrome and may also have lifelong health complications due to chest infections and asthma.

It is never too late to give up smoking, even those who have smoked for 20 years or more can realize tremendous health benefits from giving up the habit.