<jats:title>Abstract</jats:title><jats:p>Four new alkaloids, didehydrotuberostemonine A (<jats:bold>1</jats:bold>), stemoninone (<jats:bold>2</jats:bold>), tuberostemospiroline (<jats:bold>3</jats:bold>), and tuberostemonine L (<jats:bold>4</jats:bold>), together with seven known alkaloids, were isolated from the roots of <jats:italic>Stemona tuberosa.</jats:italic> Their structures were elucidated on the basis of spectroscopic analysis. The known alkaloids were identified as 2‐oxostenine (<jats:bold>5</jats:bold>), tuberostemonine (<jats:bold>6</jats:bold>), sessilifoliamide H (<jats:bold>7</jats:bold>), tuberostemonone (<jats:bold>8</jats:bold>), didehydrotuberostemonine (<jats:bold>9</jats:bold>), bisdehydrostemoninine (<jats:bold>10</jats:bold>), and tuberostemoamide (<jats:bold>11</jats:bold>).