Common Name
Castor bean, castor oil plant, higuerilla, palma Christi
Botanic Name
Ricinus communis L.
Plant Family
Waste areas, roadsides, and as cultivated ornamental. Castor bean plants have become a weed in most southern States. In northern States, the plant is grown as an ornamental annual.
Native to Africa, widely distributed globally
Animals Affected
All animals including humans.
castor bean plant showing leaves
Toxic Principle
Several toxic compounds are found in the leaves and seeds. Ricinoleic acid is the primary component of castor oil. Ricin (glycoprotein) is found in highest concentration in the seeds. The oral lethal dose of castor beans has been determined to be; horses 0.1gm/kg, sheep 1.25gm/kg, pigs 1.4gm/kg, cattle 2gm/kg, goats 5.5gm/kg. Castor oil (90% ricinoleic acid) produced from castor beans is a potent purgative. After extraction of the oil, the remaining'cake' once heat-treated is a useful, high protein food source for cattle. Ricin is a highly poisonous compound that can be absorbed from the intestinal tract, and after being metabolized in the liver, it is absorbed into cells where it inhibits ribosomal protein synthesis. Toxic effects appear within a few hours and are generally fatal. Unless the seeds are well chewed prior to being swallowed, the toxin will not be available for absorption, and signs of poisoning will be minimal if any. Birds that eat the seeds will be affected because their muscular stomach grinds the seeds to release the toxins. The leaves of the castor bean plant are also poisonous causing transitory muscle tremors, ataxia, and excessive salivation. Fatalities are rare in animals eating the leaves.
An annual or short-lived perennial, growing to a small tree in warmer climates. Leaves are large, alternate, palmate with 5-11 serrate lobes. New leaves are usually red-purple in color turning green with maturity. The male and female flowers are produced on terminal panicles. The fruit is a spiny capsule, blue-green initially, turning brown/black. Each capsule splits into 3 sections containg a shiny grey and brown mottled seed.
After ingestion of the well-chewed seeds, signs of colic and diarrhea develop. In most species pyrexia, depression, anorexia, colic and abdominal distention are initial presenting signs. Depending on the quantity of toxin absorbed, severe vomiting, weakness and hemorrhagic diarrhea may develop that results in severe shock-like symptoms and death. Rumen stasis and bloat are common in cattle.
Muscle weakness and tremors.
Castor beans should be removed from the digestive tract by inducing vomiting or administering activated charcoal, and mineral oil via stomach tube. Aggressive intravenous fluid therapy to counteract the effects of dehydration and shock are indicated. High doses of vitamin C are reported to be beneficial.
Cardiovascular system
Hypovolemic shock.
Special Notes
Do not feed castor oil cake to ruminants unless it has been heat treated. Castor bean plants should not be planted in or near livestock enclosures. References 1. Albretsen JC, Gwaltney-Brant SM, Khan SA.Evaluation of castor bean toxicosis in dogs: 98 cases. J Am Anim Hosp Assoc. 2000;36:229-233. 2. Wedin GP, Neal JS, Everson GW, Krenzelok EP. Castor bean poisoning. Am J Emerg Med. 1986;4:259-61. 3. Jensen WI, Allen JP. Naturally occurring and experimentally induced castor bean (Ricinus communis) poisoning in ducks. Avian Dis. 1981;25:184-94.
castor bean spiny fruits
castor beans (Ricinus communis)
Castor bean seed capsules - red variety
Castor bean shrub