We found 34 relevant trials covering over 16,000 participants. All except one were conducted in the USA. Some studies in dental health clinics provided advice about oral health problems to smokeless tobacco users whether or not they were interested in stopping. Some studies recruited users who wanted to stop.

Sixteen trials with 3,722 participants tested pharmacotherapies. Twelve studies tested different types of nicotine replacement therapy (five gum, two patch, five lozenge). The evidence suggests that the nicotine lozenge might help people quit, but the quality of evidence was low and more research is needed. There was not enough evidence to be sure whether nicotine gum or patches could help. Two trials of varenicline (a medication that helps smokers to quit) suggested it can also help people quit using smokeless tobacco. Two small trials of bupropion (an antidepressant that helps smokers to quit) did not find that bupropion helped people quit using smokeless tobacco.

Seventeen trials with 12,394 participants tested behavioural support. The behavioural support could include brief advice, self-help materials, telephone support, access to a website, and combinations of elements. There was a lot of variation in results with some trials showing clear evidence of benefit and some not showing any effect. We could not be certain what the important elements of effective support were, but providing access to telephone support generally seemed to be helpful.