Ricin is a poison. It is a highlytoxic, naturally occurringprotein. It is produced in the seeds of thecastor oil plantRicinus communis.
A dose the size of a few grains of table salt can kill an adult human.[1] Themedian lethal dose (LD50) of ricin is around 22 micrograms per kilogram (1.78 mg for an average adult, around 1⁄228 of a standard aspirin tablet/0.4 g gross) in humans ifinjected orinhaled.[2] Oral exposure to ricin is far less toxic and a lethal dose can be up to 30–40 milligrams per kilogram.
Ricin preventscells from assembling variousamino acids intoproteins, and death occurs after a few hours up to a day. Ricin has been used as aterrorist weapon, including theassassination ofGeorgi Markov in 1978, supposedly by theKGB.
