# Are plants ever deadly in minute doses? **URL:** \ **Category:** Factual Questions\ **Created:** [June 9, 2010, 10:33pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588 "2010-06-09T22:33:17Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [June 9, 2010, 10:33pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/1 "2010-06-09T22:33:17Z")
[This thread](http://boards.straightdope.com/sdmb/showthread.php?t=563332) in Cafe Society risks being hijacked by a discussion of poisonous plants (okay, it was briefly hijacked, and I don’t want to continue it). So I figure I’ll ask here. Are there documented cases of people getting severely ill or dying from minute doses of poisonous plants? For the purposes of the conversation, “minute dose” is defined as “less than one full leaf, chewed and then spat out.” I’m guessing that there are documented cases of such illness from poison ivy and its relatives. Are there any documented cases from any other plant? There are urban legends about oleander, but I’ve never seen documented cases. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [June 9, 2010, 11:15pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/2 "2010-06-09T23:15:37Z")
[Fox Glove](http://en.wikipedia.org/wiki/Digitalis) Wikipedia > [@](#): > > The entire plant is toxic (including the roots and seeds), although the leaves of the upper stem are particularly potent, with just a nibble being enough to potentially cause death. [Castor Beans](http://en.wikipedia.org/wiki/Ricin) are nasty too. I don’t know how much ricin would be in half of one of those hugh leaves. Wikipedia > [@](#): > > Most acute poisoning episodes in humans are the result of oral ingestion of castor beans, 5-20 of which could prove fatal to an adult. Related > [@](#): > > The U.S. Centers for Disease Control (CDC) gives a possible minimum figure of 500 micrograms (about half a grain of sand) for the lethal dose of ricin in humans if exposure is from injection or inhalation ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [June 9, 2010, 11:27pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/3 "2010-06-09T23:27:08Z")
[Belladonna](http://en.wikipedia.org/wiki/Atropa_belladonna) Wikipedia > [@](#): > > Ingestion of a single leaf of the plant can be fatal to an adult. The leaf is not the most poisonous part of the plant. ---
**Author:** ![ChrisBooth12](https://avatars.discourse-cdn.com/v4/letter/c/e95f7d/32.png) [@ChrisBooth12](https://boards.straightdope.com/u/ChrisBooth12)\ **Post date:** [June 9, 2010, 11:29pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/4 "2010-06-09T23:29:13Z")
I was always told in scouts always eat a bug/critter over a plant. Your stomach can digest venom just like its protein. Poisonous plants not so much. Brightly colored frogs need not apply ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [June 9, 2010, 11:38pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/5 "2010-06-09T23:38:01Z")
[Aconitum](http://en.wikipedia.org/wiki/Aconitum) Monkshood, Wolfsbane, Etc. Wikipedia > [@](#): > > Poisoning may also occur following picking the leaves without wearing gloves; the aconitine toxin is absorbed easily through the skin. From practical experience, the sap oozing from eleven picked leaves will cause cardiac symptoms for a couple of hours. In this event, there will be no gastrointestinal effects. Tingling will start at the point of absorption and extend up the arm to the shoulder, after which the heart will start to be affected. I’m betting there is enough of the sap in half that leaf you masticated and spit out to kill you. ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [June 10, 2010, 12:29am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/6 "2010-06-10T00:29:40Z")
> [@Harmonious\_Discord](#): > > [Belladonna](http://en.wikipedia.org/wiki/Atropa_belladonna) > Wikipedia > > The leaf is not the most poisonous part of the plant. This looked most promising, so [I followed the wikipedia cite](http://www.ema.europa.eu/pdfs/vet/mrls/054098en.pdf). I may well be reading this incorrectly, but here’s what looks important to me: > [@](#): > > The total alkaloid content of the overground parts of the plant is reported to be 0.2 to 2.0% in the dry matter…the main alkaloid of the total alkaloid complex is (s)-hyoscyamine coming up to 87.6% in the leaves…in case of (s)-hyoscyamine an oral dose of 10 mg and more is said to be lethal in human adults. So if one ate a dry leaf of potent belladonna, if I’m doing my math right, it would take 500 mg to kill. I assume that a leaf is at least 50% water, so it’d take the ingestion of 1 gram to kill. That could be a complete leaf–but remember that what I’m talking about is significantly smaller than a leaf. This is where “documented cases” would come in handy. Are there any documented cases of serious illness or death from the taste-and-spit method of plant identification, especially if poison ivy is excluded? ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [June 10, 2010, 1:11am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/7 "2010-06-10T01:11:52Z")
If you include anaphylaxic shock, you can get lethality with microscopic doses of pollen or plant matter. ---
**Author:** ![Visual\_Purple](https://avatars.discourse-cdn.com/v4/letter/v/5daacb/32.png) [@Visual\_Purple](https://boards.straightdope.com/u/Visual_Purple)\ **Post date:** [June 10, 2010, 1:12am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/8 "2010-06-10T01:12:34Z")
Dropping in without much time. Stories about oleander suggest that it might be fatal at the kind of level you are talking about. Anecdotes exist about people becoming acutely ill from using oleander twigs to, e.g., grill hot dogs. That would be one I’d pursue. I’ve been warned against handling Wolfsbane/Monkshood barehanded by knowledgeable sources, so I’d second that as another to pursue. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [June 10, 2010, 2:35am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/9 "2010-06-10T02:35:52Z")
> [@Left\_Hand\_of\_Dorkness](#): > > This looked most promising, so [I followed the wikipedia cite](http://www.ema.europa.eu/pdfs/vet/mrls/054098en.pdf). I may well be reading this incorrectly, but here’s what looks important to me: > > So if one ate a dry leaf of potent belladonna, if I’m doing my math right, it would take 500 mg to kill. I assume that a leaf is at least 50% water, so it’d take the ingestion of 1 gram to kill. That could be a complete leaf–but remember that what I’m talking about is significantly smaller than a leaf. You can’t make wild ass assumptions about organic chemicals like that. Half a leaf is 50% of a leaf. No reducing it further. ---
**Author:** ![flodnak](https://avatars.discourse-cdn.com/v4/letter/f/838e76/32.png) [@flodnak](https://boards.straightdope.com/u/flodnak)\ **Post date:** [June 10, 2010, 7:03am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/10 "2010-06-10T07:03:00Z")
If you’re willing to include mushrooms in the category of “plants” - they’re fungi, of course, but in day-to-day speech they tend to get lumped in with true plants - well, that includes things like the charmingly named [death cap,](http://en.wikipedia.org/wiki/Death_cap) which can kill you in amazingly small doses. Some experts claim you don’t even have to eat one of the dang things, it’s enough if one was carried in the same basket with edible mushrooms. [Destroying angels](http://en.wikipedia.org/wiki/Destroying_angel) are also rather nasty, particularly since they look a lot like some of the common, edible, and in fact rather tasty puffballs. ---
**Author:** ![coremelt](https://avatars.discourse-cdn.com/v4/letter/c/4491bb/32.png) [@coremelt](https://boards.straightdope.com/u/coremelt)\ **Post date:** [June 10, 2010, 7:44am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/11 "2010-06-10T07:44:40Z")
This article has some choice quotes: > **[Top 10 Most Poisonous Plants](https://www.mapquest.com/travel/top-5-poisonous-plants.htm)** > > If you swallow these plants, you could wind up with stomach convulsions, blurred vision or amnesia. You could even die. What shouldn't you taste on your next hike? Rosary Pea: Less than 3 micrograms of ab rin in the body is enough to kill, which is less than the amount of poison in one pea. Water Hemlock: No amount of water hemlock root is considered safe to ingest. Oleander: An oleander’s poison is so strong, in fact, that it can poison a person who simply eats the honey made by bees that have digested oleander nectar. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 10, 2010, 10:12am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/12 "2010-06-10T10:12:19Z")
> [@ChrisBooth12](#): > > I was always told in scouts always eat a bug/critter over a plant. Your stomach can digest venom just like its protein. Poisonous plants not so much.y That is one of the most dangerous pieces of ignorant advice that I have ever heard. Firstly, very few bugs have venom in the sense they can inject the stuff. Most bugs are just poisonous to animals that ingest them. Secondly, the fact that they have specifically evolved to be poisonous to the animals that ingest them should tell anyone with half their brain functioning that … wait for it… they are poisonous if ingested by an animal. Thirdly, many bugs actually concentrate the toxins in the plants that they feed on. They don’t make novel compounds, they just store the toxic compounds in the plant. Monarch caterpillers for example, store all the toxic glycosides that they swallow. As a result the caterpillars are orders of magnitude more poisonous than the plants they are feeding on. And if you can’t digest the toxins in the plant, how the hell are you going to be able to digest the toxins after they are concentrated in an animal? And finally, even for animals with injected toxins the advice is a load of crap. You need to remove the toxin injection system, otherwise it will sting the inside of your throat/gut and kill you. The very thought of swallowing a venomous caterpillar, jellyfish or centipede without removing the injection systems is horrifying. You’d be dead as a dodo within minutes if you tried that trick. Boy Scouts of America. Celebrating 100 years of giving lethal advice to youngsters. Our Motto: Better dead than gay. ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [June 10, 2010, 11:06am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/13 "2010-06-10T11:06:57Z")
> [@Harmonious\_Discord](#): > > You can’t make wild ass assumptions about organic chemicals like that. Half a leaf is 50% of a leaf. No reducing it further. I think that’s a non sequitur–what reduction did I make that was unreasonable to make? I never mentioned “half a leaf.” The link to mushrooms is actually what got me started on this. My mycology professor in college was the one who suggested the tiny-sample-and-spit method, telling us that there was no fungus so deadly that it could kill you, or even seriously harm you, through this method. Oleander is a possible candidate for what I’ve said–which brings us back to the question about documented cases of poisonings from minute quantities. I’ve heard the “grilling hot dog” stories so often that I mentioned and dismissed them in the OP as an urban legend; are there any **documented cases** of such poisonings? The only documented cases I’ve read of oleander poisoning entail the ingestion of multiple leaves. Pollen: heh, fair enough. I did say “deadly,” not “fatally poisonous,” so those should count. Hopefully it’s clear from my OP that I didn’t intend to include forms of fatality other than eating the leaves; otherwise you could also include injecting a tiny splinter of a plant into a vital area of the brain, or the rapid introduction of a very sharp sample of a plant to an artery. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [June 10, 2010, 11:38am UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/14 "2010-06-10T11:38:08Z")
> [@Left\_Hand\_of\_Dorkness](#): > > Oleander is a possible candidate for what I’ve said–which brings us back to the question about documented cases of poisonings from minute quantities. I’ve heard the “grilling hot dog” stories so often that I mentioned and dismissed them in the OP as an urban legend; are there any **documented cases** of such poisonings? The only documented cases I’ve read of oleander poisoning entail the ingestion of multiple leaves. The [lethal dose in monkeys](http://vet.sagepub.com/content/11/3/259.abstract) is 30mg dry leaf/kg body weight _ingested_. For an average adult human male that works out at about 2 grams for a fatal dose. For most sclerophyllous plants dry weight is ~15% wet weight. So that means the fatal dose of fresh leaf would be around 13 grams. A single leaf would be a bit over 1 gram I guess. So you’d be looking at an adult ingesting several leaves to several dozen leaves for a lethal effect. I have no idea what the dose for “seriously ill” would be, but I’m having hard time believing that a bite that was spit out would cause serious effects. ---
**Author:** ![Cheshire\_Human](https://avatars.discourse-cdn.com/v4/letter/c/5f8ce5/32.png) [@Cheshire\_Human](https://boards.straightdope.com/u/Cheshire_Human)\ **Post date:** [June 10, 2010, 8:11pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/15 "2010-06-10T20:11:12Z")
I’ve got some lovely nightshade growing here. Have a berry! ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [June 10, 2010, 8:17pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/16 "2010-06-10T20:17:48Z")
> [@Visual\_Purple](#): > > I’ve been warned against handling Wolfsbane/Monkshood barehanded by knowledgeable sources, so I’d second that as another to pursue. How silly. I’ve transplanted monkshood (Aconitum) around the garden, had the foliage come into contact with bare skin, and I’m still he ---
**Author:** ![Left\_Hand\_of\_Dorkness](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/left_hand_of_dorkness/32/7156_2.png) [@Left\_Hand\_of\_Dorkness](https://boards.straightdope.com/u/Left_Hand_of_Dorkness)\ **Post date:** [June 10, 2010, 8:41pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/17 "2010-06-10T20:41:12Z")
> [@Blake](#): > > The [lethal dose in monkeys](http://vet.sagepub.com/content/11/3/259.abstract) is 30mg dry leaf/kg body weight _ingested_. For an average adult human male that works out at about 2 grams for a fatal dose. For most sclerophyllous plants dry weight is ~15% wet weight. So that means the fatal dose of fresh leaf would be around 13 grams. > > A single leaf would be a bit over 1 gram I guess. So you’d be looking at an adult ingesting several leaves to several dozen leaves for a lethal effect. I have no idea what the dose for “seriously ill” would be, but I’m having hard time believing that a bite that was spit out would cause serious effects. Thanks, Blake–this is the sort of analysis that is, I believe, useful. Again, the gold standard would be documented cases of poisonings by minute quantities, but these may be unavailable, since most people eat either zero quantities of the substance or a significant quantity. Alternately (my hypothesis), they are unavailable because few or no plants are significantly toxic when ingested in such minute quantities. If documented cases are the gold standard, however, the opposite end must be the crap standard, and that’s got to consist of folklore, urban legends, uncited Wikipedia claims (such as the one about aconite), and snarky one-offs that have little to do with the specific question in the OP. I’m disappointed that so many replies are so low quality; is this usual for GQ? ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [June 10, 2010, 9:05pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/18 "2010-06-10T21:05:08Z")
> [@Left\_Hand\_of\_Dorkness](#): > > Thanks, Blake–this is the sort of analysis that is, I believe, useful. > > Again, the gold standard would be documented cases of poisonings by minute quantities, but these may be unavailable, since most people eat either zero quantities of the substance or a significant quantity. Alternately (my hypothesis), they are unavailable because few or no plants are significantly toxic when ingested in such minute quantities. > > If documented cases are the gold standard, however, the opposite end must be the crap standard, and that’s got to consist of folklore, urban legends, uncited Wikipedia claims (such as the one about aconite), and snarky one-offs that have little to do with the specific question in the OP. I’m disappointed that so many replies are so low quality; is this usual for GQ? Happy to do reseach for you. I won’t waste my time on you again. ---
**Author:** ![Projammer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/projammer/32/559_2.png) [@Projammer](https://boards.straightdope.com/u/Projammer)\ **Post date:** [June 10, 2010, 9:31pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/19 "2010-06-10T21:31:24Z")
[Cerbera odollam](http://en.wikipedia.org/wiki/Cerbera_odollam), the suicide tree. Not the leaves, but the berries. > [@](#): > > Cerberin is difficult to detect in autopsies and its taste can be masked with strong spices. Therefore it is often used in homicide and suicide in India. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 10, 2010, 9:54pm UTC](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588/20 "2010-06-10T21:54:23Z")
I believe **WhyNot** has some stories to tell of near-lethal poisoning just from handling datura. EDIT: [Found the thread](http://boards.straightdope.com/sdmb/showthread.php?t=492962). The rest of the thread is probably relevant to this discussion, too. [Next page](https://boards.straightdope.com/t/are-plants-ever-deadly-in-minute-doses/542588.md?page=2)