A new alkaloid named lutessine (2) has been isolated, together with its deacetyl derivative (3, from bulbs of Sternbergia lutea. The structures were elucidated by spectroscopic and chemical methods, and lutessine was identified as 1-O-acetyl-4-methoxylycorine. As part of our studies on the chemical and biological properties of lycorine (1) (1-3), we have isolated from the bulbs of Sternbergia lutea Ker-Gawl (Amaryllidaceae) the alkaloids sternbergine (4) and hippamine (5), in addition to the six alkaloids previously described (6). More recently, 11-hydroxyvittatine has been found in the same plant (7). The present work describes the isolation and the identification of the new alkaloid lutessine (2), together with its deacetyl derivative (3, from the bulbs. Lutessine (2), represents the first alkaloid that incorporates a lycorine-type skeleton but with a substituent on the D ring. It is interesting, therefore, to correlate this structural modification, in comparison with lycorine (1), in the inhibition of ascorbic acid biosynthesis in vivo (1). This bioassay of compound 2 and its deacetyl derivative is in progress.