Heimia salicifolia H.B.K. (Lythraceae), common name sinicuiche (voucher No. 7302), was collected at Villa Las Fuentes, Nuevo Leon, Mexico in November and December 1973. It is used for dysentery, chest ailments and the preparation of a hallucinogenic tea. Previous work reported 20 cis or trans lactonic biphenyl or biphenylether quinolizidine alkaloids from H. salicifolia and related species, with established structure, stereochemistry and absolute configuration; phenylalanine is a biosynthetic precursor of one major alkaloid. The taxonomic status of Heimia is unclear, and alkaloid type may vary with collection place and date. From ethanolic extracts, a high yield of mannitol was obtained. TLC comparison with known Heimia alkaloids (MeOH-Me2CO 1:1, Dragendorff reagent) showed light petrol and EtOH extracts contained sinicuichine, cryogenine and nesodine; sinicuichine and cryogenine were isolated and compared with authentic specimens by mmp, (α) and TLC. Two new alkaloids ALC-1 and ALC-2 were isolated; based on typical mass fragmentation, NMR and properties of their methyl ether derivatives, they were stereomers of lythrine (1). They exhibited Bohlmann bands in IR, indicating trans-quinolizidine derivatives. Talauma mexicana (DC.) Don, called Yoloxochitl ("flower of the heart") in Mexico, is used for fevers, heart affections, paralysis and epilepsy. In 1947, Pallares and Garza isolated an alkaloid aztequine (mp 176°) from it and proposed structure (1) using classical methods. Previously, we synthesized (1) but could not compare with natural aztequine due to unavailability. The proposed structure (1) is biogenetically questionable. We attempted to isolate aztequine from T. mexicana but found no such compound; instead, we obtained liriodenine (2).