Habeba Mahmoud Abdelmonem¹, Omar Hassan Khashaba², Medhat A. Al-Daker³, Mahmoud Darwish Moustafa^{4 1}. Demonstrator, Oral medicine, Periodontology, X-Ray & Diagnosis, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. ² Professor of Oral medicine, Periodontology, X-Ray & Diagnosis, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. ³ Professor of Medical Microbiology & Immunology, Faculty of Medicine, Mansoura University, Mansoura, Egypt. ⁴ Associate Professor of , of Oral medicine, Periodontology, X-Ray & Diagnosis, Faculty of Dentistry, Mansoura University, Mansoura, Egypt. Abstract: Objectives: To assess the clinical and microbiological effects of commercially available gel containing Aloe vera as an adjunctive therapy to scaling and root planning in the treatment of chronic periodontitis. Methods: A total of fourty patients with mild and moderate chronic periodontitis were selectively collected for contribution in the present study. This study was performed using a split-mouth design in which the patient received thorough scaling and root planning (SRP) in addition to application of Aloe vera gel to either the right or left side of dentition and thorough scaling and root planning (SRP) was only performed in the contralateral side of the same dentition. Results: Results showed that the sites treated with SRP+Aloe vera gel 100% concentrate exhibited greater reductions in P. gingivalis and P. intermedia count than sites treated with SRP alone. Also difference between control and test side was statistically significant in clinical parameters. Conclusions: Scaling and root planning was effective in improving clinical and microbiological parameters in patients with chronic periodontitis. Scaling and root planning plus Aloe vera gel (100% concentrate) exhibit bactericidal effect in the periodontal pocket of patients with chronic periodontitis. Aloe vera gel could be used for the treatment of periodontitis as a complementary therapy not to replace mechanical intervention (SRP). Keywords: Aloe vera gel; chronic periodontitis; microbiology.