Four tetrahydroisoquinoline alkaloids have been isolated from Mucuna pruriens seeds for the first time, out of which two are new. Their structures have been established by spectroscopic methods. The seeds of Mucuna pruriens (L.) DC. after chemical analysis afforded four tetrahydroisoquinoline alkaloids which have been isolated for the first time from M. pruriens. Out of them, two are new whose structures have been elucidated by spectroscopic methods. © 2004 Elsevier Ltd. All rights reserved.