Background: For improving efﬁcacy and outcomes of regenerative therapy for furcation defects, various materials has been investigated in addition to access therapy. Platelet-rich fibrin (PRF) having concentrated growth factors and cytokines and Metformin (MF), an efficacious member of biguanide group are known to enhance periodontal regeneration. The aim of the present trial is to evaluate the efficacy of PRF with 1% MF in treatment of mandibular class II furcation defects and its comparison to PRF and access therapy alone.