Apium graveolens has been shown to inhibit the growth of a variety of cancer tissues. In this study, we investigated the anticancer effect of A. graveolens on the human prostatic carcinoma cell line LNCaP. LNCaP cells were treated with increasing concentrations of an ethanolic extract of A. graveolens ranging from 1000 to 3000 mu g/mL, and viability was determined after 24 and 48 h using the XTT cell proliferation assay. The levels of cleaved poly (ADP-ribose) polymerase (PARP), one of the best biomarkers of apoptosis, were analyzed. Finally, quantitative gene expression analysis of vascular endothelial growth factor (VEGF), a critical mediator of angiogenesis, was performed using real-time reverse transcription-polymerase chain reaction. A. graveolens extract inhibited cell viability in both a time-and dose-dependent manner. Data from cleaved PARP assays suggested that A. graveolens caused induction of apoptosis in these cells. Treatment of cells with A. graveolens also resulted in downregulation of VEGF expression. This study showed that the antiproliferative effect exerted by an ethanolic extract of A. graveolens is triggered by induction of apoptosis. We also demonstrated that VEGF expression was downregulated by treatment with A. graveolens extract.