Periodontitis is an inﬂammation of the supporting structures of the teeth, usually caused by speciﬁc or groups of microorganisms that results in the progressive destruction of the periodontal ligament and alveolar bone. the objective of periodontitis treatment is to reduce the number of periodontal pathogens. However, there is not an agreement in the use of systemic antibiotics in patients with diabetes. The purpose of the present study was to determine the efficacy of amoxicillin/metronidazole compared to clindamycin during non-surgical treatment of periodontitis in patients with type 2 diabetes mellitus.