Metformin is considered an initial oral pharmacotherapy of choice for treating hyperglycemia in type 2 diabetes mellitus (T2DM). Although safe in the vast majority of the population, rare side effects will come to light as the prevalence of T2DM continues to rise. We present a rare case of metformin-induced hepatotoxicity and possibly the first reported case of dose-dependent metformin-induced hepatotoxicity. This case report aims to make clinicians aware of this infrequent yet significant adverse reaction that can arise with metformin therapy.