The present work aims to investigate the anti-cancer in-vitro activity of two plants commonly used in traditional Indian medicine - Zingiber officinale Roscoe and Nerium oleander L. The extracts of these plants was tested in-vitro on several cancer cell lines (human leukemic cell line K562, THP-1, MOLT-4 and Jurkat). Cell growth inhibition was observed for both plant extracts with IC50 values ranging between 1-28 μg/ml using SRB (Sulphorodamine B) and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. Enhanced cell growth inhibition was observed when the extracts were combined with Imatinib. Exposed cells showed cell cycle arrest, DNA damage and cytochrome c release, indicating that the mechanism of cytotoxicity could be via mitochondrial mediated apoptotic pathways. Combination of the extracts of these plants with standard cancer treatment may be one of the ways of enhancing responses. Clinical studies in chronic myeloid leukemia patients are planned at our centre.