Q and A: Lily of the Valley Poisoning

15 Nov

Q: In my novel an 82 year old woman is found dead. Lily of the Valley, ground up and put in her loose tea, is what I’m using as a poison. How much should the dosage be and how will the ME find it?

B. Giersch

A: Lilly of the Valley (Convallaria majalias) is native to Canada and the Mid-West and Western US. All parts of the plane are toxic, particularly the leaves. Water in which the cut flowers have been kept is also toxic. Though the water may yield enough toxin to be deadly, a “tea” made by boiling the leaves, would certainly contain even more of the toxin and would be a more effective poison.


The toxin in Lilly of the Valley is called convallatoxin. It is a glycoside in the same family as digitalis, which comes from the Foxglove (Digitalis purpurea or D. lanata).



How many leaves would your killer have to crumble and mix with the tea? There is no way to tell. Each plant contains a different amount of the toxin so the leaves would vary greatly in their potency. The actual amount of toxin in a teaspoon of crumbled leaves is guess work at best. This is good since you can add almost any amount and be OK. Or simply skip theamountand let the reader assume the killer added enough.

Symptoms onset quickly and include nausea, vomiting, abdominal pain, flushing, hot flashes, dilated (enlarged) pupils, a red skin rash, excessive salivation, coma, and death. These glycosides can also cause deadly alterations in cardiac rhythm, which can lead to sudden collapse and death.

A toxicological examination of the blood, urine, and stomach contents would easily uncover the toxin since glycosides are easily identified. Initially the toxicologist might only be able to say that the blood contained a glycoside but not which one. Digitalis? Convallatoxin? Further testing with gas chromatography and mass spectroscopy (GC/MS) would determine which glycoside was present and would expose the actual cause of death.


Posted by on November 15, 2010 in Poisons & Drugs, Q&A


21 responses to “Q and A: Lily of the Valley Poisoning

  1. Rin

    November 15, 2010 at 10:33 am

    Excellent, a really clear and understandable post – I’m killing off one of my characters with digitalis, so it’s been particularly useful for me to read this. Thank you!


    • D.P. Lyle, MD

      November 15, 2010 at 10:36 am

      Love to hear that. Hope your story goes smoothly.


  2. Kat Sheridan

    November 15, 2010 at 12:06 pm

    Perfect for me as well, since I also have a character (named Lily!) using lily of th valley, Fortunately, I write historical romance, so no pesky gas chromatography to deal with!


  3. Suzanne Arruda

    November 15, 2010 at 3:07 pm

    This seems to be the poison du jour as I’m also making use of it. There’s something ironic about using a plant that is the symbol of purity as a weapon


  4. Erica Obey

    November 15, 2010 at 8:18 pm

    Anne Perry did a mystery with lily of the valley as the weapon a while back. I don’t remember much except (SPOILER) it involved a woman masquerading as a male architect.

    As a gardener, I still remember my first experience with digitalis. My (then) 7-year-old, very stubborn nephew kept trying to lick it, and when I said no, he kept asking why. I was trying very hard not to scare him, but nothing turned the trick until I finally snapped in exasperation, “Because it’s POISON!”


  5. hallie ephron

    November 16, 2010 at 5:38 am

    Hey, Doug!
    Fascinating – and we have a garden full of both flowers. They volunteer (like weeds). Used to be paranoid that one of my kids would try to eat the red berries that that grow form where the flowers were. Seems to me Agatha Christie used foxglove.


  6. Laura Mitchell

    November 16, 2010 at 8:37 am

    I may be losing my mind (heck, I probably am), but I thought I saw a response about hallucinogens. Well, if this is the right list, you might want to check out Jimson Weed. Nasty stuff. I think the active ingredient is in the atropine/scopalamine family. I know about it because the plant is almost indestructible and every once and a while, a weekend gardener grafts tomato plants onto Jimson weed stalks, which ends up filling the tomatoes with the nasty stuff. Also, I know someone who’s kid smoked the stuff as a cheap high and ended up in the Emergency Department (survived, relatively intact).


  7. Laura Mitchell

    November 16, 2010 at 8:38 am

    Sorry, I almost forgot. And what about oleander? Where I live, it’s used to landscape freeways. Another nice little botanical.


  8. Sheri Fredricks

    November 16, 2010 at 10:37 am

    Dr. Doug – I clicked on your post out of curiosity and came away wow’d. Your site is now bookmarked! I have to kill someone off in my MS and this is perfect! I can’t wait to nose around here more and see what else you have! Thanks for your blog and this amazing blog site!


    • D.P. Lyle, MD

      November 16, 2010 at 11:45 am

      Welcome aboard. Hope you find lots of useful stuff here.


  9. Brian

    May 2, 2011 at 8:31 pm

    I just wanted to mention, There has been no single death on the books involving Lily of the Valley. The root is generally what is used and it’s actually used as a heart medicine. The convallatoxin you mentioned earlier is what was found to be fatal, that is, an isolated constituent, not the whole plant. Furthermore, this was injected in high dose directly into the heart of the rabbit. You would have to take a rather high amount of Lily of the Valley to actually manage to kill yourself. The herb is actually emetic (vomit inducing) in high doses so it is unlikely you will die from taking it. Additionally, convallatoxin has a very short half life and is excreted via the kidneys pretty quickly (unlike foxglove’s digitoxin which can take over 6 days to clear the body).

    Just thought I would share, the picture of overdose you painted is pretty accurate except for the coma and death. I happened to be writing a plant monograph on Convallaria majalis so I was rather surprised when I read this.

    As for the question asker: if your 82 year old were on heart medication such as blood thinners or arrhythmia controlling drugs, THEN she would certainly be at risk for complications and M.I.’s .


    • Andy

      February 11, 2013 at 2:57 pm

      Brian, Are you out there? Dr. Lyle? Or anyone? What North American plant would you recommend to kill off a 65yo wife batterer? Something from the garden or a weed. Something that can be slipped undetected into his alcohol, scrambled eggs or coffee???

      Many thanks for any suggestions! – andystanton(at)comcast(dot)net


      • D.P. Lyle, MD

        February 12, 2013 at 8:34 am

        Andy–I don’t answer questions such as this on my blog but rather only through my website as I require certain information beforehand. Please go to my site and click on the Have A Story Question? link and the instructions for submitting questions are there.


      • do8ug

        April 30, 2017 at 8:05 am

        They should make a concentrate or use the death angel mushroom or water hemlock or puffer fish like the voodoo priests use. There are so many things more toxic than most plants like aspirin or fluoride.
        I was wondering about lilly of the valley cause it looks similar to wild garlic/ramps I teach people about in my wild edible plant classes.


      • D.P. Lyle, MD

        April 30, 2017 at 12:50 pm

        Lily of the Valley can be deadly. I wouldn’t recommend eating it.


  10. mbassara

    May 18, 2011 at 7:32 am

    Well this does seem to be the poison du jour!

    Thanks for this great post and all related comments. By the way, the Anne Perry book that used lily of the valley as the murder weapon – or rather, more accurately, the water from the vase in which the flowers were displayed – was not the one about the architect (Breach of Promise), it was Weighed in the Balance.

    Thank you for a great blog, btw – it should be bookmarked by all aspiring writers of crime!


  11. Ayla

    May 26, 2011 at 2:28 pm

    I have actually accidentally eaten some of the lily-of-the-valley when I was a little girl, and I had none of those symptoms. Maybe I didn’t eat enough to get the reaction you are talking about…?


  12. A. J.

    November 26, 2012 at 10:14 am

    I have a character, male, 50, with a serious heart condition for which he takes medication. I would like to kill him with Lily of the Valley as the murderer wants the police to know how he was killed. (Long story.) You mentioned that it would be easier to kill someone who was on heart medication using the toxic elements of the plant. What precisely is the chemical reaction that causes death? I would like to be able to have the murderer put a distilled dose of the poison in a cup of coffee. Is it possible to concentrate the toxin from the plant to do this? Many thanks!

    Liked by 1 person

    • D.P. Lyle, MD

      November 26, 2012 at 10:43 am

      AJ–I don’t answer questions about stories here but you can submit your questions thru my website. I require certain information beforehand so read the instructions, supply the needed info, and then send along your questions


  13. Debra

    May 29, 2014 at 1:26 pm

    I nearly loss my horse when she ate one leaf of Lily of the Valley. She became hot, sweaty, irregular heartbeat, convulsions, disoriented and started to colic. Horses can not vomit. I called the Vet and at the time (3 or 4 years ago) was told there was nothing that could be done for her except comfort measures and if she makes it 24 hours, she will probably live. She did make it, but she was cooled down and pain medication was given around the clock. It was one of the most horrible sickness I have ever seen in a horse. The twisted bowel of the horse comes close, but the suffering from the lily of the valley nearly caused me to put her down. I still have the horse today and she certainly is my baby.

    Liked by 1 person


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: