Abstract: This invention relates to a method for obtaining castor-oil plants deprived of the ricin/RCA protein, through the insertion of gene constructs into plant cells, particularly castor-oil plant ones, with the consequent production of ricin/RCA-free castor-oil plant seeds. An aspect of the invention consists in providing castor-oil plants and parts thereof containing said gene construct. The method disclosed herein appeared to be efficient to the generation of castor-oil plants deprived of ricin protein or showing low expression levels of this protein, thus allowing the use of the seed thereof to the production of detoxified cakes, both for animal nutrition and for fertilizers, not to mention its possible production in countries that set restrictions to this substance, due to ricin toxicity. Therefore, this invention also provides a method and a kit to the identification of transformed plants containing the gene constructs disclosed herein.