Manchineel: The Most Poisonous Tree in the World

The Manchineel tree, also known as the poison guava (Hippomane mancinella), is an unusual and highly poisonous species. Like the deadly castor bean, it is a member of the spurge family. It is warily avoided by locals in the Caribbean and the Gulf of Mexico where it grows along shorelines.

Another common name for the manchineel is the beach apple — which sounds innocent enough, but eating the fruit can be fatal.

Manchineel fruits are highly poisonous, however, it’s not only the attractive-looking fruits that we should be wary of… The sap within the leaves and wood also contains a highly toxic latex that can cause very serious damage to the skin and eyes.

What Are The Active Compounds in Manchineel?

The compounds that make the manchineel tree so deadly are found within all plant parts — from the flowers to the roots. The main active compound is known as phorbol. It causes an inflammatory response in the body, and can also indirectly encourage tumor growth. Manchineel also contains saponins like the deadly pokeweed, and the fruits also contain another highly toxic alkaloid known as physostigmine.

Manchineel Poisoning Symptoms

The sap will irritate the skin and cause dermatitis and painful blistering on contact. If it gets into the eyes it may cause temporary or even permanent blindness.

Eating manchineel fruits (or any plant part) will result in severe inflammation of the digestive tract, from the mouth and throat to the intestine. The severe reaction can cause irreversible damage and would likely result in death.

Shockingly, the manchineel can also cause indirect irritation on the skin and eyes. When the wood is burned the resulting smoke can cause temporary or permanent blindness. This can make removing the tree a difficult issue as chopping or burning the trunk can be hazardous.

Even standing beneath the tree during rainfall can be dangerous as raindrops become contaminated with the potent toxins. Many people have suffered blistered skin as a result of sheltering under a manchineel tree during a storm or downpour.

Cultural Symbolism of Manchineel

The effects of manchineel have long been known to indigenous islanders who used the toxic sap to their advantage. They used the sap to create poisonous arrows, and the leaves were also supposedly used to poison the water supplies of enemies.

Over time, the main use of manchineel became a source of timber. The tree must be carefully harvested as the sap can be a huge risk to anyone cutting the wood. After harvesting, the wood is left to dry in the sun, to ensure the sap is no longer dangerous. Caribbean carpenters created furniture, cabinets, and other beautifully carved items.

Notable Manchineel Poisonings

Throughout history, manchineel has been responsible for a large number of poisonings. Local knowledge was established quickly, but many unsuspecting sailors and colonialists were poisoned as they had no local plant knowledge. Many explorers and sailors also reference manchineel in their notes, and many had written records of how they, or fellow crew, fell ill after eating or being exposed to manchineel.

Today, warning signs and markings are set up in particularly touristy areas where the trees thrive to protect other unsuspecting victims from the tree’s toxicity.

What is the Medicinal Potential of Manchineel?

Like other poisonous species, for example, the foxglove or deadly nightshade, manchineel does hold some medical potential. Like the foxglove, the dried bark of manchineel was once used in herbal recipes to treat edema. Scientific studies are limited so homemade recipes are not recommended.

What Does Manchineel Look Like?

Manchineel trees tend to reach heights of 12-15 meters. The leaves are leathery, bright green, and very slightly serrated, and the flowers are small green/yellow and inconspicuous.

The fruits resemble a small apple or guava fruit and are noted as having a slightly sweet scent. To unsuspecting foragers, tourists, and particularly children, the fruits appear harmless, but they, unfortunately, hold deadly potential.

Where Does Manchineel Grow?

This deadly tree grows along the sandy shores of the Caribbean and also around the Gulf of Mexico. They grow within mangroves and swamps in Florida, Central America, and also around the Eastern coastline of Mexico. Many trees can also be found near tourist beaches.

Conclusion

Although incredibly toxic, the manchineel does have a valuable role within its ecosystem. Because of its coastal positioning and large size, it can help to prevent coastal erosion. It is also a food source and refuge for some wildlife, like the black-spined iguana. The tree itself is endangered, so while it may be very deadly, it should be respected.

Featured Image | Photo by Hans Hillewaert on Wikimedia Commons