Jatrogrossidion, 4Z-jatrogrossidentadion, 15-epi-4Z-jatrogrossidentadion, 4Ejatrogrossidentadion,15-epi-4E-jatrogrossidentadion, 2-hydroxyisojatrogrossidion, 2-epihydroxyisojatrogrossidion and jatrowediol have been isolated from the stems of Jatropha weddelliana. The elucidation of the structure of the latter, a novel lathyrane, was accomplished by detailed NMR investigation and X-ray diffraction analysis.