Abstract: Using the MTT colorimetric assay, we studied acntitumour activities of 6 natural dinene compounds on three different tumour cell lines vs well-known antitumour drug, vinblastine (VLB). The results is that antitumour activities of the 6 dinene compounds are related with their chemical structures; the rank of their antitumour activities is; E₁₈E₂₁ > E₁₃ >VLB>E₁₉ >V₈ >E₁₂, acethyl moiety on the 6 dinene compounds is the funcational group.