A UC San Francisco survey of more...

A UC San Francisco survey of more than 1,000 major league baseball players showed that nearly half of those using smokeless tobacco at least once a week had sores in their mouths.

Among nonusers only 1% had similar sores.

Users who tucked a pinch of snuff between the cheek and gum were more likely to develop lesions than tobacco chewers. The figure for snuff users was 55% and for tobacco chewers 17%.