Red Castorbean Castorbean is cultivated for the seeds which yield a fast-drying, non-yellowing oil, used mainly in industry and medicines. The castor oil is extracted from the beans, which is used for medicinal purposes. In S. American traditional medicine the juice from the leaves is used against rheumatism, headache, ringworms and warts. Plant seeds in well drained soil, barely cover the seeds and keep only lightly moist, in filtered light. Do not keep wet. Ordering seeds info