The Cochrane systematic review promotes evidence-based outcome studies. This review was conducted to determine reliable evidence concerning the effectiveness of tongue scraping or cleaning, compared with other interventions for controlling halitosis. A competent search strategy was developed and used across several databases--including the Cochrane Oral Health Group Trials Register, the Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Google Scholar--to identify randomized controlled trials that compared different methods of tongue cleaning to reduce mouth odor in adults with halitosis. Methodological quality of studies was assessed based on criteria defined by the Cochrane Collaboration. Clinical outcome (expressed in terms of a reduction in mouth odor in adults with halitosis) was examined. The review included two trials involving a total of 40 participants. Based on the independent data from these two trials, the tongue cleaner or the tongue scraper demonstrated a statistically significant difference in reducing levels of volatile sulfur compounds (VSCs) when compared with the toothbrush. The findings indicate a small but statistically significant difference in reduction of VSC levels when tongue scrapers or cleaners, rather than toothbrushes, are used to reduce halitosis in adults.