Design: Randomised, parallel arm, double blind, placebo controlled trialInterventionForty-seven non-compliant patients with inadequate oral hygiene procedures were randomly allocated into test (22 patients) and placebo (25 patients) groups. The test group received a mouthrinse containing 0.05% CHX and 0.05% CPC as active ingredients. The placebo rinse was identical, except that it lacked the active agents. Outcome measure: Clinical, microbiological and patient centred/adverse effect measures were taken at baseline and at 3 months. The primary outcome measures were clinical changes in plaque index (Pl), measured using the modified Quigley Hein Index and changes in visual gingival inflammation (GI). Additional clinical measures were bleeding on probing (BoP), probing pocket depth (PPD), gingival recession (GR) and clinical attachment levels (CAL). Bacterial counts for subgingival and saliva samples, frequency of detection and proportions for each bacterial species were recorded as were adverse effects and patient reported side effects. Results: For the primary outcomes, there was a statistically significant (P<0.001) improvement in Pl although GI showed no statistically significant difference. For the other clinical measures, there was a statically significant reduction in BoP only. For the microbiological outcomes, there were significant differences between groups for only 2 of the 9 pathogens studied. No difference in patient centred outcomes was found between the groups. Conclusions: The authors concluded that the tested mouthrinse demonstrated efficacy in reducing plaque and gingivitis, as well as decreasing the microbial load in saliva and gingival sulcus.