The aim of this study was to investigate the effects of a simplified system of oral hygiene, comprising Bass brushing, scaling, root planing and subgingival irrigation using a pulsated monojet oral irrigator, in patients with chronic periodontitis. After initial assessment, patients received scaling, root planing and instruction in Bass brushing and in use of a pulsated jet oral irrigator (Water Pik + Imax attachment) to irrigate subgingivally. 11 patients with 262 approximal periodontal pockets used 0.02% chlorhexidine (CH), or a placebo as the irrigating solution once daily for 28 days. Plaque index (PlI), sulcus bleeding index (SBI), and probing pocket depth (PPD) were assessed on days 0, 28, 56 and 84. Within procedure comparisons for all groups showed that the regime was highly effective in reducing PlI, SBI and PPD, improvements being maintained at least until day 84. Between procedure comparisons showed that benefits were improved only marginally by the use of 0.02% CH as the irrigation fluid. The patients found the procedure pleasant and neither injuries nor staining were noted during the study. It was concluded that this simplified oral hygiene system was effective in reducing periodontal inflammation and pocket depth, although no significant added benefit with 0.02% CH was apparent. The technique may be useful in patients who cannot achieve high levels of routine mechanical oral hygiene, particularly interdentially. The effects of using higher concentrations of chlorhexidine should be investigated.