<p>A new phenolic glucoside, abeliaside, along with four known compounds, 5,6,7,4′-tetrahydroxy flavones, caffeic acid, 4-<i>O</i>-caffeoylquinic acid and caffeic acid glucoside, was isolated from the leaves of <i>Abelia triflora</i> R. Br. (Caprifoliaceae). The structure of the new compound was elucidated by different spectroscopic techniques. Compounds <b>1</b>–<b>5</b> were assayed for their anticancer activities against two cancerous human cell lines, MCF-7 and PC-3 cells, and normal Vero cell line using the crystal violet staining method. From the results it could be seen that caffeic acid possessed the highest anticancer effect against MCF-7 (IC<sub>50</sub>: 17 μg/mL) and PC-3 (IC<sub>50</sub>: 20.1 μg/mL) compared to vinblastine sulphate as reference drug (IC<sub>50</sub>: 4.6, 2.8 μg/mL). The other compounds showed weak anticancer activity on both cell lines.</p
