The objective of this study was to test the hypothesis that the application of a chlorhexidine-based decontamination protocol during two weeks prior to scaling root planing (SRP) would reduce bleeding on probing (BoP) at the time of SRP. Secondary outcomes were other clinical parameters. Another secondary aim was to assess whether the improvement of periodontal conditions, if any, would have a benefit up to 3 months later. In this mono-centre, parallel, single blind, randomised, controlled clinical study, thirty subjects affected by chronic periodontitis were randomly allocated 1:1 to either a control group (n=15, individuals subjected to a standard one-stage full-mouth disinfection procedure fifteen days after inclusion), or a test group (n=15, individuals had to apply a decontamination protocol consisting of tongue brushing and mouth rinsing with chlorhexidine-based products during the fifteen days intervening between inclusion and SRP. BoP, probing depth (PD), plaque index (Pl.I) and clinical attachment loss (CAL) were measured at the inclusion and at t SRP =baseline, when individuals were subjected to SRP, and after 30 and 90 days. Immediately before SRP, BoP was significantly reduced in test (68.31±14.70) with respect to control group (29.54±11.97, p<0.0001). The other clinical parameters (except for CAL) were significantly reduced, with comparable improvements between the two groups after 30 and 90 days. Although investigations on a larger sample are desirable, the early application of a disinfection procedure improves the condition of patients undergoing full-mouth therapy. This leads to marked advantages both for patients, who exhibit reduced bleeding, swelling and pain, and the operator, who is less operatively limited during the hygiene session.