The present study aimed to investigate the anticancer effect of rosmarinic acid (RA), both alone and in combination with cisplatin (cis). Also, the potential nephroprotective effects of RA against cis-induced nephrotoxicity in mice and the possible mechanisms underlying this protection were explored. Treatment of HepG2 cells with RA produced a significant decline in cellular proliferation. RA induced cell cycle arrest at G 0 / G 1 phase and S phase, significantly inhibited vascular endothelial growth factor (VEGF) concentration and induced caspase-3 level in cell lysate. While pre-treatment with IC 50 RA before cis addition significantly enhanced cis cytotoxic activity in HepG2 cells. Moreover, Pre-treatment with RA significantly mitigated cis-induced elevation of blood urea nitrogen (BUN) and serum creatinine levels. The elevated levels of malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), Bax and caspase-9 in kidney tissues were significantly reversed. Additionally, RA significantly abrogated cis-induced reduction in reduced glutathione level (GSH). The histopathological examination emphasized the obtained results. Conclusion: RA possesses cytotoxic activity against HepG2 cell line through cell cycle arrest, induction of caspase-3 and inhibition of VEGF. In addition, RA enhances cis-induced cytotoxicity in HepG2 cells. Also, it ameliorates cis-induced nephrotoxicity in mice; an effect which could be attributed to inhibition of oxidative stress, inflammation and apoptosis.