ricin, ricin toxin - a toxic protein extracted from castor beans; used as a chemical reagent; can be used as a bioweapon; "one milligram of ricin can kill an adult"

poison, poisonous substance - any substance that causes injury or illness or death of a living organism

animal toxin, zootoxin - a toxin resembling bacterial toxins in its antigenic properties that is found in the fluids of certain animals

bacterial toxin - any endotoxin or exotoxin formed in or elaborated by bacterial cells

cytotoxin - any substance that has a toxic effect on cells

endotoxin - a toxin that is confined inside the microorganisms and is released only when the microorganisms are broken down or die

exotoxin - a toxin that is secreted by microorganisms into the surrounding medium

hepatotoxin - any toxin that affects the liver

nephrotoxin - any toxin that affects the kidneys

neurolysin, neurotoxin - any toxin that affects neural tissues

phytotoxin, plant toxin - any substance produced by plants that is similar in its properties to extracellular bacterial toxin