ricin /rī″sin/ , a poison made from waste produced in processing castor beans. It can take the form of a powder, mist, or pellet or can be dissolved in water or weak acid and can be used as a poison by ingestion, inhalation, or injection. As little as 500 micrograms can be a fatal dose. It cannot be spread by person-to-person contact. Poisoning is treated by minimizing exposure and by supportive care. There is no antidote. Also called ricinine. See also ribosome-inactivating protein.
