Chemotherapeutic agents help in treating periodontal infection in a non surgical manner. It is a minimally invasive procedure which can be used in the treatment of periodontal pockets, intrabony defects, inflammation, abscess etc. Often, incorporation of an appropriate chemotherapeutic agent in conjunction with mechanical instrumentation provides an additional antimicrobial effect offering increased opportunity to control disease. The question that is frequently asked is what adjunctive agent is the most effective for patients with progressive periodontitis that has not responded sufficiently to mechanical therapy alone. We have attempted to review the antibiotics and other antimicrobials that have been used most frequently in adjunctive periodontal therapy and to present both the success stories and the failures.