Acute myeloid leukaemia (AML) is the most common type of leukaemia in adults and is associated with high relapse rates. Current treatment options have made significant progress but the 5 year survival for AML remains low and therefore, there is an urgent need to develop novel therapeutics. Ellipticines, a class of cancer chemotherapeutic agents, have had limited success clinically due to low solubility and toxic side effects. Isoellipticines, novel isomers of ellipticine, have been designed to overcome these limitations. One particular isoellipticine, 7-formyl-10-methylisoellipticine, has previously showed strong ability to inhibit the growth of leukaemia cell lines. In this study the anti-leukaemia effect of this compound was investigated in detail on an AML cell line, MV4-11. Over a period of 24 h 7-formyl-10-methyl isoellipticine at a concentration of 5 mu M can kill up to 40 % of MV4-11 cells. Our research suggests that the cytotoxicity of 7-formyl-10-methylisoellipticine is partially mediated by an induction of mitochondrial reactive oxygen species (ROS). Furthermore, 7-formyl-10-methylisoellipticine demonstrated promising anti-tumour activity in an AML xenograft mouse model without causing toxicity, implying the potential of isoellipticines as novel chemotherapeutic agents in the treatment of leukaemia.