A glucanhydrolase (a DXAMase exhibiting both dextranolytic and amylolytic activities) from Lipomyces starkeyi KSM 22 hydrolyzed polysaccharides having ${alpha}-(1{ ightarrow}3)-,;{alpha}(1{ ightarrow}4)-,;and;{alpha}-(1{ ightarrow}6)$-D-glucosidic linkages. The oral hygiene benefits of DXAMase-containing mouthwash were examined in relation to human experimental gingivitis during a 3-week period without brushing. The DXAMase-treated group exhibited a lower increase in plaque accumulation and gingival index score than the chlorhexidine-treated group. The DXAMase-treated group also showed less tongue accumulation, bad taste, and tooth staining, thus indicating a positive role for DXAMase as an antiplaque agent ingredient.