Marama cotyledon ethanolic extract (MCE) offered similar and/or higher protection against cytopathic effects of RV than that offered by antiviral drug Combivir on all intestinal epithelial cells, with higher effect on CIEB and H4 cells. Exposure of CLAB cells to seed coat and cotyledon water and ethanolic extracts at concentrations lower than IC 50 resulted in higher survival of the cells. This could be due to potentiated toxic effects due to combined presence of RV and extract (at IC 50 concentration) and diluted cytotoxicity at lower extract concentrations. This effect was cell culture dependent, implying possible different interspecies responses.