The aims of this study were to assess the effects and potential mechanisms of parthenolide on the expression of vascular endothelial growth factor (VEGF), interleukin 8 (IL-8) and matrix metalloproteinase 9 (MMP-9) in human breast cancer cell line MDA-MB-231. After incubation with different concentrations of parthenolide for 24 h, MDA-MB-231 cells were collected, and the expressions of VEGF, IL-8 and MMP-9 were measured by real-time PCR and Western blot. The secretions of VEGF, IL-8 and MMP-9 in culture supernatant of MDA-MB-231 cells were then measured with ELISA assays. The NF-κB DNA-binding activity of breast cancer cells treated with parthenolide was analyzed using electrophoretic mobility assays. The real-time PCR and Western blot data showed that the expressions of VEGF, IL-8 and MMP-9 were significantly inhibited by parthenolide at both transcription level and protein level in MDA-MB-231 cells. ELISA results also confirmed these effects at a secretion level. The electrophoretic mobility assay results demonstrated that parthenolide can inhibit NF-κB DNA-binding activity of the breast cancer cells. Hence, the expression of VEGF, IL-8 and MMP-9 may be suppressed by parthenolide through the inhibition of NF-κB DNA-binding activity in MDA-MB-231 cells. Copyright © 2012 John Wiley & Sons, Ltd.