Objective: The study compared two commercial chlorhexidine mouthrinses (Chlorhexamed 0.1% and Corsodyl 0.2%) for their effects on dental plaque and gingival inflammation, thei r side effects (eg, tooth staining and mucosal irritation), and patient acceptance. Method and materials: One hundred thirty halthy volunteers were randomly distributed into two groups of 65 each. Each volunteer had gingivitis or chronic marginal periodontitis and used the rinse two times a day for 4 weeks. The sulcular bleeding index, approximal plaque index, gingival index, and a discoloration index were taken at baseline and once a week thereafter. The patients were questioned about taste disturbances, mucosal irritation, and their perception of the taste of the mouthrinse. Results: In both groups, after 4 weeks, the mean sulcular bleeding index, approximal plaque index, and gingival index scores had decreased significantly. The discoloration index had increased significantly in both groups. There were no statistically significant differences between the two mouthrinses in any of these measurememts. There were no significant differences in side effects reported by the two groups. Conclusion: The increase in concentration of chlorhexidine provided no clinical advantages or disadvantages.