Periodontitis is a multifactorial disease that can lead to the destruction of supporting tissues of the teeth resulting in pocket formation, recession or both. Since the primary etiological factors for periodontal disease are bacteria in supra and sub gingival biofilm, efforts for disease prevention and treatment are mainly focused on pathogen reduction and strengthening of epithelial barrier, thus contributing to decreased susceptibility to infection. Due to emergence of antibiotic resistance and frequent recolonization of treated sites with pathogenic bacteria, there was need for a new treatment paradigm to be introduced to periodontal disease. The need was fulfilled by the introduction of Probiotics and Bacterial Replacement Therapy. The term probiotic is derived from the Greek, meaning "for life" are microorganisms proven to exert health promoting influences in humans and animals. Food and Agriculture Organization and WHO have stated that there is potential for probiotic foods to provide health benefits and that specific strains are safe for human use.

Inclusion Criteria:

1. Subjects in both sexes
2. Age 25 - 60 yrs
3. Subjects with mild to moderate chronic periodontitis, as defined by probing pocket depths ≥ 5mm in > 30 % of the probing sites
4. Subjects in good general health

Exclusion Criteria:

1. Antibiotic therapy in the past 2 months
2. Allergic to doxycycline or probiotics
3. Subjects with diabetic mellitus, hypertension and psychiatric disorders
4. Subjects who are pregnant/ lactating
5. Smokers and/or alcoholics
6. Subjects who have undergone any periodontal therapy within last 6 months.