The effectiveness of a mouthwash based on triclosan in combatting plaque and gingivitis was compared with a mouthwash based on nonsaponifiable maize germ (Zea mays L). Both were used to supplement conventional mechanical oral hygiene. The study was carried out under double-blind conditions with a negative control (a placebo) and a positive control (a mouthwash based on chlorhexidine). After a period of 14 days to allow the Plaque Index and Gingival Index to standardize, the 43 subjects who formed the sample were examined weekly for 3 weeks. During the study, five subjects were excluded because they did not meet criteria for selection for the study. Although the mouthwash based on triclosan reduced the Plaque Index by 7.3% in comparison with the placebo negative control (a less marked effect than that of chlorhexidine, which achieved an 8.43% reduction), it had scarcely any effect on th e Gingival Index. The mouthwash based on Zea mays L had no beneficial action on the Plaque Index, which increased slightly, but it led to an improvement in the Gingival Index (7.17% in comparison with the placebo).