Tuesday, December 4, 2007

Toxicology Tuesday, December 4

Before my sister had these evergreen shrubs removed from her front yard, I took some photos for the blog. Does anybody know what they are, and if they are



Toxic or Not?

Answer: Toxic

especially to horses. This is Taxus, common name yew, which has many varieties. I don't know which one this is,
nor does it matter as the toxicity is the same. With toxic plants, it is always important to specify what part(s) of the plant are toxic and to what species. In this case, the wood, bark, leaves, and seeds are all toxic, but not the fruiting structure, the aril (the red "berry.")

In horses and cattle, which are usually poisoned accidentally when someone throws the tasty clippings into the stall or pasture or if yew bushes are planted next to a fence, even one mouthful can be fatal. There are usually no signs, other than "found dead." The toxic agents, alkaloids called taxines, affect the electrical conduction of the heart, resulting in sudden heart failure and death. Rarely, there may be a delay of one to two days before symptoms - weakness, trembling, difficulty breathing, slow heart rate - are seen.

While yew is also toxic to pets and to birds, it is not commonly eaten by these animals. Cases in dogs are usually related to a bored puppy chewing on whatever is at hand. If you see this happen, induce vomiting immediately and take the pet to a veterinarian, as seizures may occur in dogs. There is no specific antidote for taxines, leaving decontamination and supportive care as the only treatment options.

11 comments:

Lisa at Greenbow said...

It looks like a yew to me. Probably toxic to most.

Kathy said...

My "Know Your Poisonous Plants" says it is a yew (ground hemlock) plant, which has toxic foliage, bark and seeds, especially the seeds. Not a nice plant to have in one's yard! Glad your sister got rid of it.

littleorangeguy said...

I believe it is a Hick's yew. And those seeds look nasty.

littleorangeguy said...

Oops, hit "publish" too quickly. We have three in our yard, and I've never seen an animal (cat, squirrel, or skunk) go near it with any intent to nibble, chew, or swallow any part. They provide a beautiful evergreen presence and, if they are toxic, it seems the little critters know this.

donaldthebirder said...

Taxus. I know they use this plant for making a heart medicine called Taxol, so I would say it would cause heart problems - toxic. I have heard that the red berry (aril) does not contain the chemical that causes the toxicosis.

KGMom said...

Looks like yew to me. Without research, can't be sure on the toxic, but I would think so. Not sure why though. Why would the bushes adapt to having bright red berries if they are not to be eaten. OK for birds?

nina said...

Yew.
We have a large, sprawling cluster in our yard--makes great cover for the birds and hideouts for rabbits and other small animals, especially in winter months when other trees and bushes are bare.
I was always warned as a child to not eat its berries,...so I don't.

KatDoc said...

Well done! "Yew" all did great with this one. Bonus points to Donald, who knew that the effect was cardiac, and that the correct name for the "berry" is aril.

Although the fruit is the only part of the plant which doesn't contain taxines (the toxic agent), I still wouldn't eat them. Remember, the seed is inside that aril, and it is toxic..

In terms of having it as an ornamental plant in your yard, if you like it, plant it. I doubt it would cause any problems with dogs or cats. Just keep it away from horses.

~Kathi

holly said...

I still like yew...like anything with red berries in the wintertime!

Kathi, with most toxins causing so many of the same symptoms, how on earth do you guys ever narrow it down in order to treat???? That boggles my mind, esp. given that animals aren't watched every second so owners don't always know and the patients themselves can't tell you what they ate. Y'all are GOOD.

Lisa said...

One thing I read said to make sure not to try using a yew branch as a perch in a bird cage.

All I know is ugly bush = removed from my yard.

KatDoc said...

Dear Holly,

The short answer is - We don't.

It is easy when you know the toxin to list the signs you may see, but much harder when you are presented with a sick animal to guess the cause. As you may have noticed, most toxic plants, and many other poisons, cause nonspecific vomiting and diarrhea. In addition, most toxins have no specific antidote. Treatment is limited to decontamination (induce vomiting, gastric lavage [= "pump the stomach", cathartics, activated charcoal) and supportive care (IV fluids, drugs to control vomiting, seizures, etc.)

Case in point: I had a Lab puppy present recently with very acute onset of profuse vomiting and diarrhea. I was certain the puppy had been poisoned on something, and treatd her with basic supportive care. She got better in 12 hours. I questioned the owner up, down and sideways about potential toxins in the home, the garage, the yard, etc., etc., all answers being negative. I still have my suspicions, but could never prove what the agent was.

I had a similar case last year where I did discover the cause, but since it is an upcoming Toxicology case, I don't want to give it away too soon. Stay tuned!

~Kathi