April 22, 2015

Toxicoses in the gardens

By Elizabeth Francis

As my time here is wrapping up, I think I will probably do a series of short blog posts on topics that at one point I was considering spending a lot of time on. So first up, here’s a short bit on toxicology inspired by my trip to the National Botanical Gardens (possibly one of my favorite places in DC!). I hope I do The Antidote proud.

Sorghum spp.


While walking through an exhibit on roots and root structure, I spied my first toxic plant! It was Johnson grass (aka perennial sudan, aka sorghum)! Look at those roots- amiright!? As any vet student will tell you, sorghum species are toxic by two mechanisms- they contain cyanogenic glycosides and nitrate/nitrite. Horses, cattle and sheep are the primary species affected, and toxicosis is most common in the southwest USA. Clinical signs include incoordination progressing to ataxia and flaccid paralysis. Look out for this one, guys!


Cocoa tree

Cocoa tree


Later as I was wandering around I saw a tall, beautiful, weird looking tree with big yellow fruits hanging off the trunk. The sign proclaimed “Theobroma cocoa”– the cocoa tree. It is fitting that a tree called Theobroma would be full of theobromines, which is the toxic part of chocolate and other cocoa products. The most common species affected is obviously dogs, who commonly eat things that aren’t even food so I guess we should cut them a break for getting into chocolate. Common clinical signs are vomiting, tachycardia, arrhythmias, tremors, hyperthermia, seizures and death. This is a super common toxicity (my dog got into some a few months ago!), but that doesn’t mean it’s not serious. Take your dog to the vet if you notice they’ve gotten into any!


Taxus, aka yew

Say “taxus toxicosis” 10 times, fast


The last plant I’ll tell you about is the most common plant around- you’ve probably seen it today. It probably grows by your work or school, or outside of your grandma’s house. It’s EVERYWHERE. It’s yew.

Taxus spp. are small coniferous shrubs who’s small elliptical leaves are toxic to all species. The most common species affected are cattle, but other herbivores are not uncommon. Death can come suddenly or can occur a day or two after ingestion. Symptoms include ataxia, diarrhea, hypotension, colic, hypothermia, coma, seizures, weakness, respiratory failure, bradycardia and sudden death. Oftentimes there will be no clinical signs apparent, except a dead animal in the vicinity of a yew bush with possible evidence of foraging.

It’s very dramatic.


Look out folks, toxic plants are out there!