You know humans have done something genuinely bad when Mother Nature creates a tree that wants to hurt you. And I’m not talking about hurting your feelings, I’m talking Rocko and Vinny with baseball bats like you owe them money. They won’t kill you, because they need you to pay up and to tell your friends they mean business. That’s the manchineel tree, the Rocko and Vinny of the plant kingdom. Eat it, touch it, stand under it, hell, even look at it, and you’ll pay the price.

Manchineel fruit by Dick Culbert (CC BY-SA 2.0) [changed photo from what may actually have been a paw-paw(?) on 12/27/20]

The manchineel tree, Hippomane mancinella, is native to Florida, the Caribbean, the Bahamas, and parts of Central and South America. It grows predominately along the coastal beaches and grows up to 50 feet tall.  It has bright green leaves and small apple-like fruits that litter the beaches, waiting to be carried out to sea and washed ashore elsewhere to propagate itself.  Though known by natives for as long as they’ve been around, it was not described in modern times until the voyages of Christopher Columbus – which if you think about it is as early as a New World species could be described.

Diego Alvarez Chanca, a Spanish doctor, accomanied Christopher Columbus on his second voyage to the New World in 1493. While in the Caribbean he wrote about the manchineel (1):

“There were wild fruits of various kinds, some of which our men, not very prudently, tasted; and on only touching them with their tongues, their mouths and cheeks became swollen, and they suffered such a great heat and pain”

The fruits of the manchineel became known as “manzanilla de la muerte”, which in english translates to “little apple of death.” With a name like that, you’d think we’d learn, but 500 years later, we’re still dumb enough to try them. Even medical professionals.

While on holiday in Tobago in 1999, radiologist Nicola Strickland strolled the beaches picking up sea shells. She gazed upon small green fruits and impulsively bit into one. Finding it sweet and delicious she suggested her friend try a bite, too. She wrote of their account in BMJ (2):

“The symptoms worsened over a couple of hours until we could barely swallow solid food because of the excruciating pain and the feeling of a huge obstructing pharyngeal lump. Sadly, the pain was exacerbated by most alcoholic beverages, although mildly appeased by pina coladas”

Pina coladas….it could be worse. When she explained what she did to the locals they couldn’t believe they would do such a thing, such is the poisonous nature of the manchineel.

Manchineel tree warning by Scott Hughes via Flickr (CC BY-SA 2.0)

So we’ve covered eating.  How about touching? It happens that the manchineel exudes a toxic latex that severely irritates the skin. All parts of the manchineel are able to produce the noxious liquid, and bruising increases the amount. Owing to the thickness of the epidermis on our hands, they are rarely affected, though they still may be covered with latex and be transmitted to more “sensitive” areas. And whenever a writer uses quotation marks around the word sensitive, you know what’s coming next. In 1936 there were two male patients who had manchineel juice on their hands while urinating, and unwittingly transferred the toxic latex to their “sensitive” area (3):

“The first had severe burning pain of the penis, preventing the patient from sitting down; the lesion resembled a second-degree burn and there was total sphacelation of the skin and mucous membrane of the preputial sac. The second showed a desquammation in shreds of the mucous membrane of the glans penis.”

As a dude, I suggest that from here on out, the words “shred” and “penis” shall never be uttered or written in the same sentence ever again. Agreed? Agreed. If you’ve ever worked with chile peppers then urinated, you know how easy it can be to burn your wee-wee with capsaicin. I do it every. single. year. OK, multiple times a year. You’d think I’d learn. But let’s not forget about good ol’ #2. Oh yes, I’ve got a manchineel poo story, too. This involves a sailor that used manchineel leaves “a posteriori after post defecationem” (3). The seaman was left with painful eruptions on his anus, which is a sentence and visual I never wanted to experience. You, too? Sorry.

So now we’ve learned that we shouldn’t eat it, touch it, and especially wipe our bum with it. Surely we can at least stand near it? No, absolutely not. Why on earth would you do such a thing? This tree hates us. Haven’t you learned anything so far? Four North American 20-year olds visiting the island of Bequia, West Indies sure didn’t.

During a rainstorm the four beachgoers sought shelter for an hour under a manchineel tree during a rainstorm. When rainwater strikes the tree, it can extract latex from any part of the tree, especially if there are cuts or nicks present. The toxic water then rains and drips upon the unsuspecting shelter seekers. This is what happened with our vacationers, and all four victims had some form of contact dermatitis and and painful blistering (4). Making matters worse, the water soaked their clothing and bathing suits, thus exposing their “sensitive” areas to the painful latex infused water. All together it was an unpleasant experience for the four, but they recovered. I’m guessing they aren’t going back to the West Indies any time soon. Don’t worry though, most areas, including where our intrepid quartet took shelter, mark the manchineel trees as dangerous with a red stripe and post signs, like this:

Manchineel tree warning by Gael Chardon via Flickr (CC BY-SA 2.0)

Much like “a steering wheel is not an arrow,” a manchineel tree is not an umbrella. So surely we can at least look at it, right? Wrong. Ocular injuries are extremely common from the manchineel tree. It usually occurs when one is cutting down the tree or hacking away at branches and leaves. Only a small amount of latex whipped off of a tree branch can cause damage to the corneas and cause keratoconjunctivitis – inflammation of the cornea and eyelid. Most of these injuries are resolved within a few days, but some injuries have been severe and lasted up to five years (5). People are also harmed from flying sawdust as they process the tree for lumber.  It seems that the toxic properties are eliminated after curing the wood. But humans aren’t the only victims, as pack animals are also susceptible as their eyes brush against the manchineel leaves, leading to temporary blindness (6).

So why would anyone want to keep this tree around? Well, it’s root system helps keep the beaches from eroding, which is a good thing. Best not to upset Mother Nature any more. The wood can also be used as lumber, and if you live on an island, you use what is available.

Historically, there are many myths and legends surrounding the manchineel (6). A popular one is that native South Americans used manchineel poisoned arrows against the invading Spanish Conquistadors. It is often written, but not confirmed, that Ponce de Leon, of Fountain of Youth fame, was killed by such a poisoned arrow in Florida. I’m sure there’s a “day late, fountain short” joke in there somewhere. It is also reported that natives would poison spring waters with manchineel leaves, as a defense against their invaders (6).

The burning question, I’m sure, is “what makes the manchineel tree so toxic?” That’s a complex answer, because it isn’t any one chemical. The manchineel latex is a mosaic of chemical compounds, which are difficult to separate and identify (7). Common chemicals though are deoxyphorbol esters (shown on the left) and corresponding alcohols. Of importance is the lack of alkaloids – nitrogen containing natural compounds. Alkaloids, like nicotine or strychnine, are bitter, and serve as a warning. The manchineel fruit, devoid of alkaloids, are sweet. This makes it tempting for children and visitors alike. And no matter how many warning signs you put up, someone is going to try them. Especially with pina coladas around.

So just remember, Mother nature is in charge, and she put the manchineel tree here to remind us. Don’t eat, don’t touch, don’t look. Just stay away.

*** Featured homepage image of Manchineel tree warning by Arctic Whirlwind via Flickr (CC BY-ND 2.0) ***

References:
1. Ybarra, A. M. F. De. “A Forgotten Worthy, Dr. Diego Alvarez Chanca, Of Seville, Spain.” JAMA: The Journal of the American Medical Association XLVII.13 (1906): 1013-017.
2. Strickland, N. H. “My Most Unfortunate Experience: Eating a Manchineel “beach Apple”” Bmj 321.7258 (2000): 428.
3. Earle, K.vigors. “Toxic Effects of Hippomane Mancinella.” Transactions of the Royal Society of Tropical Medicine and Hygiene 32.3 (1938): 363-70.
4. Blue, Lauren M., Christopher Sailing, Christopher Denapoles, Jordan Fondots, and Edward S. Johnson. “Manchineel Dermatitis in North American Students in the Caribbean.” Journal of Travel Medicine 18.6 (2011): 422-424.
5. Pitts, J. F., N. H. Barker, D. C. Gibbons, and J. L. Jay. “Manchineel Keratoconjunctivitis.” British Journal of Ophthalmology 77.5 (1993): 284-88.
6. Lauter, W. M., Lauretta E. Fox, and William T. Ariail. “Investigation of the Toxic Principles of Hippomane Mancinella, L. I. Historical Review.” Journal of the American Pharmaceutical Association 41.4 (1952): 199-201.
7. Adolf, W., and E. Hecker. “On the Active Principles of the Spurge Family, X.Skin Irritants, Cocarcinogens, and Cryptic Cocarcinogens from the Latex of the Manchineel Tree.” Journal of Natural Products 47.3 (1984): 482-96.