To examine the effectiveness of chlorhexidine mouthrinse (CHX) in addition to daily plaque control on gingival inflammation. Fifty gingivitis patients were randomized to CHX or placebo groups. In addition to proper plaque control, CHX group rinsed with CHX, while placebo group rinsed with placebo mouthrinse for 4 weeks. Gingival crevicular fluid (GCF) samples were collected and clinical parameters including plaque index (PI), papillary bleeding index (PBI), calculus index and probing depth (PD) were recorded at baseline and repeated at 4 week. GCF IL-1alpha, IL-1beta, IL-1Ra, and IL-8 levels were determined by ELISA. Whole mouth clinical parameters were significantly improved in both groups at 4 weeks. CHX group showed greater reduction in the mean PI scores than placebo at 4 weeks (p < 0.05). GCF IL-8 levels of anterior sites significantly reduced in CHX and placebo group at 4 weeks (p < 0.05). GCF IL-1alpha, IL-1beta, IL-1Ra levels remained unchanged at 4 weeks in both groups. GCF cytokine levels of CHX group were similar to those of placebo at 4 weeks. Within the limitations of this study, CHX mouthrinse as adjuncts to daily plaque control could be useful in management of plaque-associated gingivitis, although ineffective on GCF cytokine levels.