BACKGROUND: Use of smokeless tobacco (ST) can lead to nicotine addiction and health problems including periodontal disease and oral cancer OBJECTIVES: To assess the effects of behavioural and pharmacotherapeutic interventions to treat ST use. SEARCH STRATEGY: We searched the Cochrane Tobacco Addiction Group trials register (February 2004), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2004), MEDLINE (January 1966-February 2004), EMBASE (1988-January 2004), CINAHL (1982-February 2004), PsycINFO (1984-February 2004), Database of Abstract of Reviews of Effectiveness (DARE, The Cochrane Library, Issue 1, 2004). SELECTION CRITERIA: Randomized trials of behavioural or pharmacological interventions to help users of ST to quit, with follow-up of at least six months. DATA COLLECTION AND ANALYSIS: Two authors independently extracted data. MAIN RESULTS: One trial of bupropion did not detect a benefit of treatment after six months (Odds Ratio (OR) 1.00, 95% Confidence Interval (CI): 0.23 to 4.37). Three trials of nicotine patch did not detect a benefit (OR 1.16, 95% CI: 0.88 to 1.54), nor did two trials of nicotine gum (OR 0.98, 95% CI: 0.59 to 1.63). There was statistical heterogeneity among the results of eight trials of behavioural interventions included in the meta-analysis. Three trials showed significant benefits of intervention. In a post-hoc analysis the trials of interventions which included an oral examination and feedback about ST-induced mucosal changes had homogeneous results and when pooled showed a significant benefit (OR 2.41 95% CI: 1.79 to 3.24). REVIEWERS' CONCLUSIONS: Behavioural interventions should be used to help ST users to quit. Pharmacotherapies have not been shown to affect long-term abstinence but larger trials are needed.