Plants and bacteria make highly potent toxins that are thought to protect them from viral infections and/or to assure their survival. The deadly toxin ricin, derived from castor beans and a byproduct of castor oil production, has been implicated in espionage, murder, and bioterrorism. To date, there is no approved vaccine to protect individuals against ricin, classified by the Centers for Disease Control and Prevention as a Category B biological agent, which means it is relatively easy to disseminate. In the 1980s, Ellen Vitetta, Ph.D., and her research group postulated that if they could link a portion of the ricin toxin to a cancer-seeking antibody, they could selectively kill tumor cells and leave normal cells undamaged. In this lecture, Dr. Vitetta will review how taking toxins from bench to bedside has been interesting, unpredictable, and scientifically challenging