Background: To evaluate the effects of intraalveolar placement of gel containing 0.2% chlorhexidine and 10gm of metronidazole on the incidence of alveolar osteitis., Material and Methods: A total of 300 impacted third molars were extracted in 150 patients enrolled in this trial. In each subject a socket was randomly selected and packed to the crest of alveolar ridge with the gel. The contralateral socket was packed with placebo dressing. The occurrence of dry socket was assessed during 3rd and 5th postoperative days .The data was analysed using a meta analytical program., Study Design: Double blind, prospective, placebo controlled trial., Results: The combination of metronidazole + chlorhexidine gel significantly reduced dry socket incidence from 22.6% to 6.6% ( P ≤ 0.001) [McNemar and chi-square tests]., Conclusions: The decrease in incidence of adverse reactions and complications related to local application of metronidazole and chlorhexidine gel explains its clinical use, specifically in mandibular molar extractions where the chances of dry sockets are high. Key words: Chlorhexidine, dry socket, intra-alveolar, metronidazole, placebo., Competing Interests: Conflict of interest statement:The authors have declared that no conflict of interest exist.