β 1‐Solamargine and three new glycoalkaloids, robustine, N‐hydroxyrobustine, and 25‐acetoxyrobustine, have been isolated from the roots of Solanum robustum, the structures of which have been elucidated as 3‐O‐{O‐α‐L‐arabinopyranosyl‐(1→3)‐O‐[α‐L‐rhamnopyranosyl‐(1→2)]‐ O‐[α‐L‐rhamnopyranosyl‐(1→4)]‐(β‐D‐glucopyranosyl}solasodine (3)), its N‐hydroxy, and its 25‐acetoxy derivative. These compounds have characteristic structures in comparison with the hitherto known Solanum glycoalkaloids. (Formula Presented.) Copyright © 1994 WILEY‐VCH Verlag GmbH & Co. KGaA