Euphorbia heterophylla (EH) is a well-known Africa medicinal plant, which has been used in the African traditional medicine for the treatment of various human ailments including tumours and cancers. Previous phytochemical screening of E. hetrophylla has detected many flavonoids, terpenoids and sterols (Okeniyi et al., 2012: Silva et al., 2019). Seven compounds were isolated from the different fractions of EH including three biflavonoids (Cupressuflavone, Quecertin and Quercitrin) and four diterpenes (13-epicupressic acid, imbricatholic acid, 3α-hydroxy sandaracopimaric acid and β− hydroxysandaracopimaric acid). All the compounds were tested for their cytotoxicity against the A549 cell lines and compared with the anticancer standard etoposide. Cupressuflavone and 13-epicupressic acid showed the highest cytotoxicity against human lung cancer cells lines (A549) with IC50 values of 58 and 73µM respectively. The current findings support the traditional use of EH for the treatment of tumours and other cancer related diseases. It is suggested that the cytotoxic activity revealed in the polar MeOH fractions was due to the presence of cytotoxic bioflavonoids and the cytotoxicity observed with the non-polar fractions of E. heterophylla root were contributed by various cytotoxic terpenes.