Objective: To evaluate the clinical efficacy of Verbena officinalis Linn decoction for patients with chronic generalized gingivitis in a double-blind randomized controlled multicenter clinical trial. Method and Materials: The patients in the test group and the control group were instructed to brush and floss. Additionally, the patients in the test group were asked to rinse their mouths with a V officinalis L decoction. The primary clinical outcome was the Gingival Index (GI). The GI and Plaque Index (PI) were measured at baseline (day 0), day 14, and day 28. Results: Two hundred and sixty patients participated (control group = 130, and test group = 130). The clinical features of both the test and control groups were improved progressively throughout the time durations of day 0, day 14, and day 28 represented by highly significant decreases in both GI and PI (P .001). The Mann-Whitney test revealed significant differences between the control and test groups for GI and PI at the 14-day examination and the 28-day examination (P .001). At the beginning of the clinical trial, nonsignificant clinical differences were found following the statistical analyses of both GI (P = .981) and PI (P = .920) between the test and control groups. Conclusions: The tested V officinalis L decoction demonstrated efficacy in reducing tested indices and thus has a promising ameliorative effect for treating patients with chronic generalized gingivitis. Clinical Significance: V officinalis L decoction has good clinical results with no adverse effects. Keywords: chronic generalized gingivitis, decoction, double-blind, randomized controlled multicenter clinical trial, Verbena officinalis Linn