The aim of this study was to investigate the effects of using 0.2% Chlorhexidine digluconate in an pulsated jet irrigator by patients as part of their daily dental home-care measures. After initial assessment, 16 patients diagnosed as having adult periodontitis received scaling and polishing together with advice on the subgingival use of a pulsated jet oral irrigator with which they were supplied. 8 patients having 293 active sites with probing depths equal to or in excess of 4 mm used 0.2% chlorhexidine digluconate (CHX) in the oral irrigator, 2 x daily for 56 days. The other group of 8 patients with 253 active sites over 4 mm used a placebo as the irrigating solution. A modified dichotomous plaque index (MPI), gingival bleeding index (GBI) and probing pocket depths (PPD) were assessed on days 0, 28 and 56. Within-group comparisons showed that the CHX regime reduced MPI, GBI and PPD significantly but that the placebo group (PG) only achieved a significant reduction in the PPD. Between-group comparisons showed that the use of 0.2% CHX as an irrigant was significantly more effective than the placebo solution at reducing all the clinical parameters studied. The patients found the oral irrigator easy and pleasant to use, although all the CHX group developed staining to a varying extent. This double blind study demonstrated that 0.2% CHX used 2 x daily in an oral irrigator was effective at reducing plaque deposition, periodontal inflammation and probing pocket depths. The effects of using lower concentrations of chlorhexidine digluconate in this regime need to be investigated.