Control of plaque biofilm is central to prevention of gingivitis. In addition to professional care, effective oral hygiene measures are known to improve gingival health. The objective of this study was to investigate the effect of chitosan/blackberry-extract, delivered in a chewing gum, as an adjunct to oral hygiene, on gingival inflammation and plaque biofilm accumulation. In this 12-week randomized controlled study, the use of chitosan/blackberry-extract gum was compared to placebo in 34 subjects (17/17). Plaque index(mPI) and gingival index(mGI) were the main outcome measures followed at baseline, week 2, 4, 8, and 12. Measured patient compliance and mPI had no significant difference between experimental and control at any interval during the study. mGI was significantly lower for the experimental group compared to control at 12 weeks(P<0.005). Chitosan/blackberry-extract chewing gum may be beneficial in reduction of clinical signs of gingival inflammation and has potential as an adjunct to routine oral hygiene.