BACKGROUND In recent years, the new treatment and technology developing quickly however, the disease prevention therapy necessary investigate in preventive dentistry. Oil pulling is a traditional Indian folk remedy and Researchers et al previously first time investigated this method. Asokan S, Emmadi P, Chamundeswari et al have indicated the antibacterial activity of sesame oil against on oral microorganisms and found the bacterial growth decreased 20%. In our country, this has not been investigated thus . AIM The aim of this study to assess the antimicrobial efficacy of sunflower oil for reducing micro bacterial count in the oral cavity. METHODS The present study was a parallel design, double-blind, randomized clinical trial with two groups which collected from 162 dental students at the MNUMS, School of Dentistry. The participants rinsed a mouth by 10 ml oil 5 min twice a day after meal and all participants used the same teeth paste during the study period. Oral health status and plaque index were obtained and assessed at baseline and after 30 days of oil therapy . RESULTS However, the Oral health status index not reduced after 30 days. The baseline bacterial count mean of treatment group: a) 0-15 colons subgroup increased from 40.4% to 55.4%, b) 16-200 colons subgroup reduced from 33.3% to 28.6% and c) >201 colons subgroup reduced from 26,3% to 16.1%. In the control group no differences the bacterial count means on baseline and after therapy. CONCLUSION The oil rinse therapy can be used as valuable preventive agents in maintaining and improving oral health furthermore reduced plaque formation and bacterial colonization 15%.