In this investigation we have analyzed the synergism for the cytotoxic effect of a proprietary guggul gum extract (GU), 2-deoxy-D-glucose (2-DG) and metformin (Met) in SJRH30 human alveolar rhabdomyosarcoma and HepG2 hepatoma cell lines in vitro. 2-DG and Met as single agents have weak cytotoxic effects in both cell lines. However, the combination of GU+2-DG, GU+Met and 2-DG+Met showed synergism for cytotoxic effect by CompuSyn analysis. Therefore, GU can be included in the combination of drugs involving 2-DG and Met to have synergistic effect. GU also showed a dose-dependent increase in cellular glucose uptake in HepG2 cells like the antidiabetic drug 2,4-thiozolidine dione (TZ). The demonstration of synergism of anticancer effects between GU, metformin and 2-DG, suggest that their mechanisms are in general complementary, though further studies are required to delineate the mechanism of GU, 2-DG and metformin combinations.