Besides one aporphine, two benzylisoquinolines, and four bisbenzylisoquinolines previously known, Gyrocarpus americanus has furnished five new dimeric alkaloids: O-methyl limacusine (1), gyrocarpusine (3), gyroamericine (5), gyrolidine (7), and gyrocarpine (8). The interesting feature is the presence of 6’-hydroxy or 6-hydroxybisbenzyltet-rahydroisoquinoline alkaloids. Structures were ascertained by 360 MHz 1H nmr. © 1986, American Chemical Society. All rights reserved.