<jats:title>Abstract</jats:title><jats:p>Three new phenolic compounds, eucalmaidin F (<jats:bold>1</jats:bold>), (3<jats:italic>S</jats:italic>)‐5‐guaiacyl‐3‐hydroxypentanoic acid (<jats:bold>2</jats:bold>), and 8‐<jats:italic>β</jats:italic>‐<jats:italic>C</jats:italic>‐glucopyranosyl‐5,7‐dihydroxy‐2‐isobutylchromone (<jats:bold>3</jats:bold>), were isolated from the branches of <jats:italic>E. maideni</jats:italic>, together with 30 known compounds, including four phenylpropanoids, three lignans, four phloroglucinol glucosides, five dihydroflavonoids, seven simple phenolic compounds, six terpenoids, and glycerol. The new structures were established by spectroscopic studies (MS, and 1D‐ and 2D‐NMR), chemical degradation, and modified <jats:italic>Mosher</jats:italic>'s method. Compounds <jats:bold>3</jats:bold>, guaiacylglycerol, 3‐hydroxy‐1‐(4‐hydroxyphenyl)propan‐1‐one, caffeic acid, (2<jats:italic>E</jats:italic>)‐3‐(4‐hydroxyphenyl)prop‐2‐enoic acid, (7′<jats:italic>S</jats:italic>,8<jats:italic>R</jats:italic>,8′<jats:italic>R</jats:italic>)‐lyoniresinol, (+)‐lyoresinol 3<jats:italic>α</jats:italic>‐<jats:italic>O</jats:italic>‐<jats:italic>α</jats:italic>‐<jats:sc>L</jats:sc>‐rhamnopyranoside, garcimangosone, phlorocetophenone 2′‐glucopyranoside, (+)‐taxifolin 3<jats:italic>α</jats:italic>‐<jats:italic>O</jats:italic>‐<jats:italic>α</jats:italic>‐<jats:sc>L</jats:sc>‐rhamnopyranoside, (+)‐aromadendrin, (+)‐taxifolin, resveratrol, piceatannol, 3,4,5‐trihydroxyphenol. Tachiaside, gallic acid, macrocapals A und G, and oleuropeic acid were evaluated for their cytotoxicities against five human cancer cell lines. Resveratrol, piceatannol, gallic acid, and macrocapal G exhibited moderate inhibitory effects on human myeloid heukemia HL‐60 cell, with <jats:italic>IC</jats:italic><jats:sub>50</jats:sub> values of 22.05, 22.05, 7.75, and 31.93 μ<jats:sc>M</jats:sc>, respectively; and only macrocapal G showed inhibitory effect on hepatocellular carcinoma SMMC‐7721 cell, with an <jats:italic>IC</jats:italic><jats:sub>50</jats:sub> value of 26.75 μ<jats:sc>M</jats:sc>.