If you think smokeless tobacco is safer than cigarettes, you should think again. Smokeless tobacco has been linked to oral cancer, high blood pressure, cardiovascular disease and nicotine addiction, as well as gum disease and tooth decay. It also causes bad breath and stained teeth. Smokeless tobacco is becoming increasingly popular among teenage boys; in fact, about half of boys between 13 and 18 have used smokeless tobacco, and 20 percent are regular users, according to a study by Consumer Reports.

Smokeless tobacco is used in two forms. "Snuff," the finer grained of the two, comes in cans or pouches. A piece of it, called a "pinch," a "quid" or a "dip," is put between the lower inside cheek and gums, and the juice is sucked out of it.

The other form, called chewing tobacco, comes in long strands and is sold in pouches. An individual portion is called a "plug," a "wad," or a "chew."

Once you've used either form for a week or two, the inside of your lips usually begin to dry out and wrinkle, and may crack, bleed, and develop sore spots. Gray or white precancerous lesions called leukoplakia might also develop.

Toxic substances from smokeless tobacco are absorbed through the tissues of the mouth and from there pass throughout the body. Some of these substances are nicotine, lead, formaldehyde, cadmium (a chemical found in car batteries) and uranium 235 (a component of nuclear weapons). In fact, scientists have identified at least 28 carcinogens (cancer-causing agents) in smokeless tobacco products, including nitosamines and formaldehyde.

If you chew tobacco, your risk of oral cancer skyrockets. In fact, if you use smokeless tobacco, you are four to six times more likely to develop oral cancer than a non-user. If not identified and treated early, oral cancer has a very poor five-year survival rate. Even if treated and cured, it can still result in life-long disfigurement, distorted speech, and pain.

Affects the entire body Smokeless tobacco users often have a chunk in their mouths the entire day. The nicotine it contains is absorbed directly into the bloodstream, giving the users a "nicotine buzz." This nearly instant, somewhat euphoric feeling is what makes chew and snuff so highly addictive. Users crave more and more each day.

"Choosing between cigarettes and smokeless tobacco is like choosing between being run over by a speeding truck or a speeding car," said W. R. Spence, M.D., the author of S mokeless Tobacco: A Chemical Time Bomb . "Their effect on your health is equally deadly."