AIM: To eva luate the effect of subgingival placement of doxycy-cline in the form of a resorbable membrane on the clinical and microbiological parameters in the treatment of inflammatory periodontal disease. Material and methods; We evaluated the effects of a controlled release system containing doxycycline both in vivo and in vitro conditions. Drug systems were prepared for both, and a total of 19 patients were included in the study with age range from 35 to 50 years. Clinical parameters like gingival index, probing depth, attachment loss, and gingival shrinkage were evaluated along with microbiological evaluation as well for a period of 10 weeks. RESULTS: In vitro study showed that the doxycycline hydroxy-propyl methylcellulose films are capable of releasing the drug in a sustained way with respect to time. It was observed that the gingival index score, periodontal probing depth, and gingival shrinkage showed low levels at the doxycycline-treated sites as compared to the placebo group. The microbial culture results also showed a marked reduction in the total anaerobic count post-treatment and till the end of the 10 week study period in the doxycycline-treated group. Thus, overall results showed that 30% doxycycline methylcellulose strips have significant effects and benefits on clinical and microbial parameters in more than 5 mm deep periodontal pockets. CONCLUSION: We conclude that 30% doxycycline both in vivo and vitro study has proven to be an effective antibiotic of choice both clinically and microbiologically. CLINICAL SIGNIFICANCE: Doxycycline has proven to have great promise as an antibiotic of choice. Thus, there is a significant advantage in the clinical use of doxycycline formulation for both the therapist and the patient. It can help dental professionals as an additional means to maintain an improved clinical health in periodontal problems of their patients. With this new therapeutic modality, we can augment the ability to treat periodontitis more effectively.