Phytochemical investigations on the flower of Erythrina arborescens resulted in the isolation of eight new Erythrina alkaloid, erytharborines A–H (1–8), together with 17 known alkaloids. Erytharborines A/B (1–2) and C (3) possessed an 2H-imidazole ring and a unique oxime moiety, respectively. The structures were elucidated on the basis of UV, IR, mass spectrometry and NMR spectroscopic data.