To investigate the cytotoxic effect of some Bangladeshi medicinal plant extracts, sixteen Bangladeshi medicinal plants were successively extracted with n-hexane, dichloromethane, methanol and water. The methanolic and aqueous extracts were screened for cytotoxic activity against healthy mouse fibroblasts (NIH3T3) and three human cancer cell lines (gastric: AGS; colon: HT-29; and breast: MDA-MB-435S) using the MTT assay. Two methanolic extracts (Hygrophila auriculata and Hibiscus tiliaceous) and one aqueous extract (Limnophila indica) showed no toxicity against healthy mouse fibroblasts, but selective cytotoxicity against breast cancer cells (IC50 1.1-1.6 mg/mL). Seven methanolic extracts from Limnophila indica, Clerodendron inerme, Cynometra ramiflora, Xylocarpus moluccensis, Argemone mexicana, Ammannia baccifera and Acrostichum aureum and four aqueous extracts from Hygrophila auriculata, Bruguiera gymnorrhiza, Xylocarpus moluccensis and Aegiceras corniculatum showed low toxicity (IC50 >2.5 mg/mL) against mouse fibroblasts but selective cytotoxicity (IC50 0.2-2.3 mg/mL) against different cancer cell lines. The methanolic extract of Blumea lacera showed the highest cytotoxicity (IC50 0.01-0.08 mg/mL) against all tested cell lines among all extracts tested in this study. For some of the plants their traditional use as anti-cancer treatments correlates with the cytotoxic results, whereas, for others so far unknown cytotoxic activities were identified.