How long do you have to chew tobacco before you start to develop mouth cancer?

Nobody knows.: Everyone has a certain risk for developing cancer based on their genetics, lifestyle, habits, etc... The more exposure to tobacco you have the more your risk goes up. It's hard to be more specific than that.

No time set: It can take many years of chewing tobacco to develop changes in the oral tissue that can lead to cancer. However, mouth cancer can result from many other reasons. The best approach is to avoid using these products that are carcinogenic and have your doctor examine any oral or body lesions you might notice as soon as possible.

Cumulative: Cumulative effect over time. See oral surgeon or ENT doc if you have any of these symptoms: Persistent mouth sore, persistent mouth pain, a lump or thickening in the cheek, a white/red patch on the gums, tongue, tonsil, or lining of the mouth, a sore throat, hoarseness or feeling that something is caught in the throat that does not go away, difficulty swallowing/chewing.