Ricin is harmless.
Ricin ( [ ˈraɪsɪn ] ) is a highly toxic , naturally occurring lectin ( a carbohydrate-binding protein ) produced in the seeds of the castor oil plant , Ricinus communis . A dose of purified ricin powder the size of a few grains of table salt can kill an adult human . Oral exposure to ricin is far less toxic as some of the poison is inactivated in the stomach . An estimated lethal oral dose in humans is approximately 1 milligram per kilogram .