The toxic tree

In 1999, radiologist Nicola Strickland went on a holiday to the Caribbean island of Tobago, a tropical paradise complete with idyllic, deserted beaches. On her first morning there, she went foraging for shells and corals in the white sand, when the holiday quickly took a turn for the worse.

Scattered amongst the coconuts and mangoes on the beach, Strickland and her friend found some sweet-smelling green fruit that looked much like small crabapples. Both foolishly decided to take a bite, and within moments the pleasant, sweet taste was overwhelmed by a peppery, burning feeling and an excruciating tightness in the throat that gradually got so bad they could barely swallow. The fruit in question belonged to the manchineel tree (Hippomane mancinella), sometimes referred to as beach apple or poison guava. It’s native to the tropical parts of southern North America, as well as Central America, the Caribbean, and parts of northern South America.

The plant bears another name in Spanish, arbol de la muerte, which literally means “tree of death”. According to the Guinness World Records, the manchineel tree is, in fact, the most dangerous tree in the world. As explained by the Florida Institute of Food and Agricultural Sciences, all parts of manchineel are extremely poisonous, and “interaction with and ingestion of any part of this tree may be lethal”.

Manchineel belongs to the large and diverse Euphorbia genus, which also contains the decorative Christmas poinsettia. The tree produces a thick, milky sap, which oozes out of everything — the bark, the leaves and even the fruit — and can cause severe, burn-like blisters if it comes in contact with the skin.

This sap contains a range of toxins, but it’s thought that the most serious reactions come from phorbol, an organic compound that belongs to the diterpene family of esters. Because phorbol is highly water-soluble, you don’t even want to be standing under a manchineel when it’s raining — the raindrops carrying the diluted sap can still severely burn your skin.