Background: Periodontitis is an ongoing inflammatory reaction to oral biofilm. Clinical signs of the disease include loss of connective tissue attachment and bone around the teeth, as well as the formation of periodontal pockets due to apical migration of the junctional epithelium. MMP and cytokines are examples of inflammatory mediators that are produced as part of the host response and contribute to tissue destruction. To avoid periodontal surgeries for deep pockets, several local drug delivery (LDD) systems have been developed to avoid the negative effects of systemic antibiotic administration. Metformin (MF) is a biguanide and one of the most commonly used oral hypoglycemic drugs in type 2 diabetes. MF reduces plasma glucose by inhibiting glucose production by hepatic cells in the liver. Aside from lowering blood glucose levels, MF may have additional benefits such as weight loss, lower plasma lipid levels, and the prevention of some vascular complications. Method: a 45 old male patient diagnosed with stage III periodontitis, was treated with SRP combined with intrasulcular application of 1% Metformin gel at the deepest pocket of 6 mm PD and 5 mm CAL and follow up period 6 months. Results: 1% Metformin gel improved the periodontal health with statistically significant improvement in the PPD, CAL, PI and GI values. Conclusion: The use of 1% metformin gel as adjunct to nonsurgical periodontal therapy (NSPT) provided a significant improvement in the clinical periodontal parameters.