Objective To explore the cytotoxic activity of the alcoholic extracts of some medicinal plants used traditionally to treat cancer in Chhattisgarh state, India. Methods In-vitro cytotoxicity of alcoholic extracts of five plants i.e. Artocarpus heterophyllus, Alangium salvifolium, Buchanania lanzan, Sesbania grandiflora and Wrightia tinctoria was studied against human breast cancer (MCF-7) and human leukemia (HL-60) tumor cell lines, using the thiazolyl blue test (MTT) assay. Results Alcoholic extract of Sesbania grandiflora exhibited a prominent inhibitory effect against MCF-7 (IC 50 7.00±0.08 μg/mL) and HL-60 (IC 50 18.50±0.60 μg/mL) under in vitro condition. Conclusions From the result it can be found that the Sesbania grandiflora extract has potent in vitro cytotoxic activity.