A few commonly grown plants are poisonous. Generally, poisoning is unlikely unless large quantities are ingested (for example, if the leaves and other components are concentrated into a paste or brewed into a tea) or the plant is highly toxic. Highly toxic and potentially fatal plants include castor beans, jequirity beans, poison hemlock, and water hemlock, as well as oleander and foxglove, which contain digitalis glycosides. Few plant poisonings can be cured by specific antidotes. (See also Overview of Poisoning Overview of Poisoning Poisoning is the harmful effect that occurs when a toxic substance is swallowed, is inhaled, or comes in contact with the skin, eyes, or mucous membranes, such as those of the mouth or nose... read more .)
Many other plants cause less serious toxic effects (see table Moderately Poisonous Plants Moderately Poisonous Plants A few commonly grown plants are poisonous. Generally, poisoning is unlikely unless large quantities are ingested (for example, if the leaves and other components are concentrated into a paste... read more ).
Castor beans contain ricin, an extremely concentrated poison. Ricin has been used in assassination attempts and as a mass-casualty weapon Toxins as Weapons "Toxin" is often loosely used to refer to any poison but technically refers only to a poisonous chemical produced by an organism (although some toxins can now also be produced synthetically)... read more . Castor bean seeds have a very tough shell so the bean must be chewed to release the poison.
Jequirity beans contain abrin, a related and more potent toxin than ricin. They can cause death after swallowing. Children can die after chewing only one bean.
Poisoning from castor beans or jequirity beans may cause severe vomiting and diarrhea (often bloody) after a delayed period. People later become delirious and have seizures. They may become comatose and die. Doctors sometimes try to flush the beans out of the stomach and intestines before they are absorbed.
Oleander, foxglove, and the similar but less toxic lily of the valley can cause vomiting and diarrhea, confusion, irregular heartbeat, and high levels of potassium in the bloodstream. These plants contain a substance very similar to the heart drug digoxin. Doctors sometimes treat people who are poisoned by these plants with a drug used to treat digoxin overdose.