A phytochemical study of Senecio iodanthus and Senecio bracteatus afforded the new pyrrolizidine alkaloid iodanthine (3) in addition to the four known alkaloids retroisosenine (1), bulgarsenine (2), mulgediifoliine (4), and (12S)-12-hydroxyretroisosenine (6). The structure and absolute stereochemistry of the new compound (3) were determined by its spectral properties and confirmed by an X-ray diffraction analysis.