I've been very interested in castor beans since the time that my Korean grandmother told me that it was ok to eat the leaves.
The poison Ricin is a protein extracted from the Castor Bean. One milligram will kill an adult. The ricin works by destroying ribosomes in cells. Castor beans also carry the poison RCA(Ricinus communis agglutinin). This poison makes the blood coagulate but dones not get past the intestinal wall. Though extremely dangerous, castor beans make beautiful plants. You only have to remember not to eat the beans.