Background:It has been long recognized that periodontal diseases are infections of the periodontium, comprising the bacterial etiology, an immune response, and tissue destruction. Treatment strategies aiming primarily at suppressing or eliminating specific periodontal pathogens include adjunct use of local and systemic antibiotics as part of nonsurgical periodontal therapy. Unwanted side effects and resistance of microorganisms toward antibiotics due to their widespread use have modified the general perception about their efficacy. Research in phytosciences has revealed various medicinal plants offering a new choice of optional antimicrobial therapy. Cymbopogon citratus, Stapf. (lemongrass) is a popular medicinal plant. At a concentration ≤2%, lemongrass essential oil inhibits the growth of several kinds of microorganisms including periodontal pathogens, especially the reference strains Actinomyces naeslundii and Porphyromonas gingivalis, which were resistant to tetracycline hydrochloride.Aims:To evaluate the efficacy of locally delivered 2% lemongrass essential oil in gel form as an adjunct to scaling and root planing, as compared to scaling and root planing alone for the treatment of chronic periodontitis.Materials and Methods:2% Lemongrass essential oil gel was prepared and placed in moderate to deep periodontal pockets after scaling and root planing.Results:Statistically significant reduction in probing depth and gingival index and gain in relative attachment level were noted in the experimental group as compared to the control group at 1 and 3 months.Conclusion:Locally delivered 2% lemongrass essential oil gel offers a new choice of safe and effective adjunct to scaling and root planing in periodontal therapy.