<jats:title>Abstract</jats:title><jats:p>A phytochemical investigation of the bulbs of <jats:italic>Crinum asiaticum</jats:italic> L. var. <jats:italic>sinicum</jats:italic> <jats:sc>Baker</jats:sc> resulted in the isolation of two new alkaloids, asiaticumines A and B (<jats:bold>1</jats:bold> and <jats:bold>2</jats:bold>, resp.), together with 21 known compounds, including nine alkaloids, four amides, five phenolic compounds, and three flavonoids. All 23 compounds were isolated for the first time from <jats:italic>Crinum asiaticum</jats:italic> L. var. <jats:italic>sinicum</jats:italic> <jats:sc>Baker</jats:sc>. Their structures were elucidated by spectroscopic methods. In addition, ten alkaloids, <jats:bold>1</jats:bold>–<jats:bold>10</jats:bold>, were evaluated for their cytotoxic activities against human tumor cell lines A549, LOVO, HL‐60, and 6T‐CEM. Compounds <jats:bold>3, 4</jats:bold>, and <jats:bold>7</jats:bold>–<jats:bold>10</jats:bold> selectively showed remarkable inhibition against one or more of the tested cell lines.