Smokeless tobacco products consist of tobacco or a tobacco blend that's chewed, inhaled or sucked on rather than smoked. It's available in three main forms ::

Chewing tobacco. This type of smokeless tobacco comes in loose leaf, plugs or twists. As the name suggests, it's chewed.

Snuff. This product is available dry or moist, in loose leaf or in pouches that look like small tea bags. A pinch of snuff may be placed between the cheek and the gum or inhaled into the nostrils.

Betel quid. A product of India, Africa and Asia, betel quid is produced commercially or made at home. It consists of a dried paste that often includes tobacco, areca nuts, catechu, and scent or flavoring. Catechu is a plant-based product used to treat diarrhea and sometimes used for birth control in some parts of the world. Areca nuts are a plant-based product often used as a recreational drug. Betel is placed in the mouth, usually between the gum and cheek, and gently sucked and chewed.

Chewing tobacco and other forms of smokeless tobacco cause tooth decay. That's because chewing tobacco contains high amounts of sugar, which contributes to cavities. Chewing tobacco also contains coarse particles that can irritate your gums and scratch away at the enamel on your teeth, making your teeth more vulnerable to cavities.

The sugar and irritants in chewing tobacco and other forms of smokeless tobacco can cause your gums to pull away from your teeth in the area of your mouth where you place the chew. Over time you can develop gum disease (gingivitis) and possibly tooth loss.

Smokeless tobacco increases your heart rate and blood pressure. Some evidence suggests that it may put you at an increased risk of heart attack. People who use smokeless tobacco also have higher cholesterol levels than those who don't use tobacco. And a study published in June 2007 in the medical journal The Lancet showed a connection between the use of one form of smokeless tobacco (snus) and an increased risk of pancreatic cancer.

People who use smokeless tobacco are more likely to develop small white patches called leukoplakia inside their mouths where the chew is most often placed. These mouth lesions are precancerous — meaning that the sores could one day develop into cancer. After stopping tobacco usage, the lesions usually go away in a few weeks or a few months.

Your risk of oral cancer is increased if you use smokeless tobacco. Oral cancer includes cancers of the mouth, throat, cheek, gums, lips and tongue. Surgery to remove cancer from any of these areas can leave your jaw, chin, neck or face disfigured.