L. is a genus of the family that comprises over 600 taxa. Representatives of the genus were used as natural medications for many diseases. Methanolic-aqueous extracts from aerial parts of two species: Gruner and (Lipsky) Wagenitz were studied for their polyphenolic composition and potential protective effect on cardiomyocytes treated with doxorubicin. Effectiveness of doxorubicin in cancer therapy is limited by a dose-dependent cardiotoxicity. Oxidative stress is a widely recognized mechanism of this phenomenon. One of the most important strategies has been an application of drug together with antioxidant agents. A cardioprotective effect of selected extracts of species was suspected in this study. Cell viability, oxidative stress, and mitochondrial membrane potential analyses showed protective activity of the methanolic extract of and . on rat cardiomyocytes treated with doxorubicin. Although is more effective as a cardiomyocyte protective agent, in higher concentrations it weakened the drug activity. extract did not change the doxorubicin efficacy in the evaluated experiment. Interestingly, both tested extracts were cytotoxic for myeloma cells. The detected antioxidant activity of the studied extracts can be used in the prevention of doxorubicin-induced cardiotoxicity.