Local drug delivery system and its use in periodontal therapy is few of revolutions in field of dentistry where contemporary systemic drugs delivery methods are being replaced by the use of this newer kind of therapy, which recognises its ultimate goal by being placed directly into the site of action in lower dosage and its gain for results in higher concentration. This is a series of studies which are put forth for its pros and cons along with evidences for its use in periodontal therapy. The use of various broad spectrum antimicrobial drugs used locally that does includes tetracycline, doxycycline, minocycline, metronidazole and chlorohexdine, there site specific mechanism of action,therapeutic uses and there comparison with each other when used alone and over systemic antibiotics are being defined clearly.
