Cancer represents a major societal problem, claiming over one million victims in the United States every year. One of the more difficult aspects of treating this disease is that over 50% of cancers exhibit a phenomenon known as multidrug resistance (MDR), in which the cancer cells demonstrate resistance to a variety of chemotherapeutic drugs. A group of naturally occurring plant compounds knows as flavonoids have demonstrated the potential to interfere with the cell membrane pump that mediates the MDR observed in these cancers. It was therefore hypothesized that treatment with the flavonoid compound, flavone, would increase the efficacy of the chemotherapeutic drug, doxorubicin, by reversing MDR in multidrug resistant cancer cells. In order to test this hypothesis, cultured MDR and non-MDR human uterine sarcoma cell lines were subjected to treatment with doxorubicin alone, flavone alone, or a combination of both doxorubicin and flavone for forty-eight hours, after which time cell viability was analyzed. Results indicated that treatment with doxorubicin alone killed twice as many cells in the non-MDR strain as the MDR strain, as expected. Interestingly, cells treated with flavone alone also exhibited high levels of lethality for both cell lines. Finally, the interaction between doxorubicin and flavone had a statistically significant effect on viability of the cell lines. Depending on the concentration of flavone, interactions were shown to be additive, synergistic, or antagonistic. Overall, the results suggest that the use of naturally occurring substances such as flavone could prove useful in reversing the MDR phenotype of many cancers and thus increasing the efficacy of chemotherapy. However, the observed cytotoxicity of flavone would have to be overcome since flavone is not discriminative between cancerous cells and healthy cells. If this concentration could be found, it could have significant potential as a co-chemotherapeutic agent.