Ricin

A) SUMMARY: Minimal toxicity is expected, if the beans are swallowed intact without chewing. Ricin is considered among one of the most toxic compounds known to man. It is theorized that a single castor bean may be severely toxic and even lethal to a child. Different estimates have been made for the minimal lethal dose to adults and may be influenced by a number of variables, such as the qualities (eg, size and weight) of the castor beans ingested, as well as the patient's own comorbidities.
B) CASTOR BEANS: These beans contain approximately 1% to 10% of ricin. Estimates for minimal lethality include 8 to 10 castor beans or 30 mg up to 1 mg/kg for an adult. However, there are case reports of children ingesting 2 or more castor beans and adults ingesting up to 30 castor beans with survival, though they did have symptoms of gastroenteritis.
C) RICIN INJECTION: An injection of less than 3 mcg/kg of ricin is thought to be able to cause death.
D) ABRIN: The abrin content in a single Abrus precatorius seed is approximately 0.15%. Though there is a case report of death following ingestion of a single bean, there are also reports of survival after ingestion of multiple abrin beans.