Previous reports have described an accelerated induction of new attachment and repair of furcations in dogs after treatment of roots surfaces with citric acid, but few controlled clinical studies have examined its usefulness in surgical treatments for periodontitis. This study compared the effects of a comprehensive surgical plaque control procedure with or without citric acid treatment for generalized and localized effects on gingival height, probing pocket depth and attachment level in 72 teeth in 3 patients who were treated surgically for moderate periodontitis and examined every 3 months for 1 year. No statistically significant differences in the effects of the 2 treatments were observed. These observations suggest that there is no clinical advantage of citric acid conditioning of the root surface during surgical treatment of periodontitis.