Killer Seeds

Along the banks of an African river, spiky reddish flowers cast a short shadow. The flowers hold shiny, purplish‑brown seeds. The seeds are ripe. A gentle wind blows, and some of the seeds tumble to the ground. A curious bird wanders by looking for a meal. Though the castor bean seeds sparkle like jewels, the bird passes them by. It knows these seeds can kill.


Castor beans are the deadly part of the world’s most poisonous plant.

Castor bean plants came from tropical Africa, but they now are grown in gardens and houses around the world. The plant itself is considered exotic and beautiful for gardens and yards. And yet, the castor bean plant holds the Guinness Book of World Records’ title for world’s most poisonous plant.

Within these seeds is a deadly poison called ricin. Scientists say ricin is more poisonous than cyanide. It’s more poisonous than rattlesnake venom. A small handful of seeds can kill a person.

The poison is this plant’s adaptation. It protects the seeds from being eaten and destroyed before they can sprout and make more plants. For humans to safely handle the plants, the seeds must be heated to neutralize the poison.

The Sting Is the Thing

In a tropical rain forest in Australia, there grows a tree with heart‑shaped leaves. Each leaf of the gympie‑gympie tree is coated with shimmering fuzz. It’s beautiful, but watch out!

The fuzz you see is actually made up of hollow, needle‑like hairs. Each is filled with a toxin painful to people. You only need to lightly touch the plant to get stung. The hairs penetrate your skin and break off. They’re so tiny that often the skin will close over the hairs, trapping them.

Native animals, like the green possum, can happily climb into these trees and even eat their leaves and fruits with no ill effect. Humans, horses, and dogs, however, are another story. They can experience a crippling pain after brushing against the plant.

While the plant causes an immediate burning sensation, it doesn’t actually harm the body or do lasting damage. But it’s best to immediately wash the needles from the skin to be pain free.


The hair‑like needles of the gympie‑gympie carry a painful toxin.