Diabetes mellitus (DM) is caused by either destruction of pancreatic β-cells (type 1 DM) or unresponsiveness to insulin (type 2 DM). Conventional therapies for diabetes mellitus have been developed but still needs improvement. Many diabetic patients have complemented conventional therapy with alternative methods including oral supplementation of natural products. In this study, we assessed whether Ginkgo biloba extract (EGb) 761 could provide beneficial effects in the streptozotocin-induced type 1 DM and high-fat diet-induced type 2 DM murine model system. For the type 1 DM model, streptozotocin-induced mice were orally administered EGb 761 for 10 days prior to streptozotocin injection and then again administered EGb 761 for an additional 10 days. Streptozotocin-treated mice administered EGb 761 exhibited lower blood triglyceride levels, lower blood glucose levels and higher blood insulin levels compared to streptozotocin-treated mice. Furthermore, liver LPL and liver PPAR-α were increased whereas IL-1β and TNF-α were decreased in streptozotocin-injected mice treated with EGb 761 compared to mice injected with streptozotocin alone. For the type 2 DM model, mice were given high-fat diet for 60 days and then orally administered EGb 761 every other day for 80 days. We found that mice given a high-fat diet and EGb 761 showed decreased blood triglyceride levels, increased liver LPL, increased liver PPAR-α and decreased body weight compared to mice given high-fat diet alone. These results suggest that EGb 761 can exert protective effects in both type 1 and type 2 DM murine models.