Is poison green?
March 22, 2008 9:41 AM   Subscribe

Why is green the iconic color of poison?

Poison is often represented as being green. In video games, for instance, something dripping poison or a vial of poison is more likely to be green than any other color. Outside of video games, term "poison green" is sometimes used to denote a bright, slightly bluish green. Given that so many healthy foods are green, where did this association come from? Are there actual poisons, toxins, or venoms that are bright green? Absinthe doesn't count.
posted by L. Fitzgerald Sjoberg to Science & Nature (36 answers total) 13 users marked this as a favorite
I've often wondered if it isn't due to a (sub)conscious dislike/fear of nature, given how many shades of green appear there. I think this might be especially true of those who live cut-off from the real world, working at computers all day and staying inside when not at work. Just a hunch, never seen anything concrete along these lines.
posted by OlderThanTOS at 9:54 AM on March 22, 2008

Copper arsenite can't have helped green's reputation.
posted by Mr. President Dr. Steve Elvis America at 10:01 AM on March 22, 2008 [1 favorite]

Most auto coolant is green and toxic.
posted by found missing at 10:03 AM on March 22, 2008

I meant to link to the article on Scheele's Green, but I got Scheele instead.
posted by Mr. President Dr. Steve Elvis America at 10:11 AM on March 22, 2008

Well, in terms of things like video games, cartoons, etc., the other major color choices would obviously signify something else, no? Dripping red would be blood; dripping blue would be water; dripping yellow would be...pee, most likely. In other words, because green liquid doesn't obviously signify something else -- and therefore seems intuitively unnatural, perhaps? -- it seems logical to me that it would become the default signifier of poison in those circumstances.

Of course, I would assume this association may go back much further than the creation of color TV monitors. As others have pointed out, several poisons and chemicals are green. Also, keep in mind that the whole "greens are healthy!" is a relatively new idea in terms of food knowledge and wide access to produce -- even a hundred years ago, it's not like most people were eating salad on a regular basis. For most people, "green" and "food" would signify spoilage (like mold, or potatoes that go green).
posted by scody at 10:13 AM on March 22, 2008

I think of that color of green as being iconographically the color of toxic or radioactive waste (for example in the 1973 Dr. Who show The Green Death) where the glow indicates some kind of dangerous energy the substance is emitting. I was going to cite Cyalume light sticks as an example of this greenish glow, but apparently that color is due to a dye added to the chemical mixture, so clearly our expectation that a glowing liquid is green in color runs deep, even in something that isn't threatening. It would of course be threatening if consumed, and I wonder if the color of auto coolant isn't added as a warning not to drink it, rather than inherent in the substance.
posted by Horace Rumpole at 10:13 AM on March 22, 2008

Bile = green = vomiting = devilry = poison
(historically speaking, kinda thing)
posted by peacay at 10:14 AM on March 22, 2008

I think it has to do with the connotations of un-natural-ness. For example, the green radioactive stuff in Half Life just looks dangerous, due to its oversaturated hue.
posted by fvox13 at 10:19 AM on March 22, 2008

Ah, and here's something about green and the development of toxic pigments: "Discovery of the pigment emerald (Schweinfurt green) in 1800 further worsened the repute of green as the color of poison. Emerald was prepared from verdigris and copper arsenite to result in one of the deadliest poisons ever used in painting." Emerald green was also called Paris green, and it was evidently used as a rat poison and insecticide.
posted by scody at 10:20 AM on March 22, 2008 [5 favorites]

I always assumed it was because green isnt traditionally a natural color for internal body fluids (blood and such). Example being that if you got cut or infected, the infected pus and fluids were yellow or green-----so over time green became associated with all things "un-healthy".

There might be other influences (hemlock?, poison-ivy?) and so for survival purposes, it probably became a well-advised rule to avoid anything that contained green fluids. The modern world just capitalizes on that mental association and it feels "natural" to us to associate the color green with poisonous (un-healthy) things.
posted by jmnugent at 10:38 AM on March 22, 2008

interesting question. when i read scody's reply, I immediately though of the rodent poison D-CON; It's green. From working in a lawn & garden store, I also remember poison-treated lawn seed being dyed green.
posted by ArgentCorvid at 10:39 AM on March 22, 2008

"Green was a symbol of budding love in the Middle Ages. The Romans associated green with Venus, goddess of love. - It's also a symbol of poison: Green dye used to be produced with copper and toxic arsenic."
posted by cashman at 10:48 AM on March 22, 2008 [1 favorite]

Green is the color of spores and mold. Contaminated food often turns green.
posted by tkolar at 10:50 AM on March 22, 2008 [1 favorite]

Ach, this is easy. If food will kill you after being outside for a long time, it turns green. Like rotten meat or gangrene. So poison is green.
posted by markovich at 10:58 AM on March 22, 2008

Green is also the color of envy, which is another kind of poison.
posted by acorncup at 11:03 AM on March 22, 2008

It's also the color of envy. And everyone knows envy will kill you.
posted by watercarrier at 11:04 AM on March 22, 2008

Green's association with radioactivity might also be due to uranium's use in glass making. Uranium glass is a vivid green.

Trinitite, a silicate/feldspar residue found in the Trinity nuclear test crate, was also a distinctive light green.
posted by Iridic at 11:05 AM on March 22, 2008

Mr Yuck is mean. Mr Yuck is green. (warning: link plays the Mr Yuk song)
posted by happyturtle at 11:07 AM on March 22, 2008 [1 favorite]

I always assumed it was because green isnt traditionally a natural color for internal body fluids

Right, and while vegetables are generally green, there are not many natural drinks, like juices, that are green, especially in Western culture. So a green liquid is almost by definition not natural in any way, therefore presumed poisonous.
posted by beagle at 11:09 AM on March 22, 2008

I assume this isnt a question of "what real life poison is green," but why choose this color. The history of this stuff is in printed media like flyers and textbooks. So if you look at the tradition RYB color wheel you'll see that green is one of the brighter colors. Usually black and red are used for more serious items, but green and yellow are incredibly bright compared to them. This is why you dont see too many dark red firetrucks anymore, but you'll see a lot of green and yellow emergency vehicles nowadays.

Considering Mr. Yuk is from 1971, I'd guess that this may be the color and symbol gen-x videogame designers and artists are influenced by. He's, of course, green. Also its worth noting that medical bottles produced post-industrial revolution came only in a few colors. Green was one of them. Perhaps there an association with these bottles and the chemicals they contained, many of which were toxic. Vintage green apocathary bottles might have been the inspiration for Mr. Yuk too.
posted by damn dirty ape at 11:10 AM on March 22, 2008

The historical question is interesting. Is green = poison a cultural universal? The connection to mold and rot is compelling.

Green = envy is very culture specific. In Germany, yellow is the colour of jealousy.
posted by Nelson at 11:25 AM on March 22, 2008

It's not as simple as saying green = poison. Green is also a good color (growing, spring, evergreen, young). But green light and green people are kind of weird.

What color of human skin is worst? We have all sorts of reds and yellows and browns and purples. It's the stuff in the blue and green part of the spectrum that would look weird in a human. Blue is suffocation (or Smurfication) but at least it occurs. It's green that just doesn't happen in any sort of normal situation (except maybe dead). Mr Yuck is not just a green substance, but a green-skinned man, so something must be seriously wrong with him.

And radiation: it has no visible color, but you have to have a color in something as simplistic as a comic book or video game. What color of light would be least natural? We have all sorts of pinks and purples and blues and so on in the sky, and the sun and fire are yellow and orange, but how often do you see green light in nature? There are a few things you can burn to get green flames, but generally green is a weird sort of light.

Also, a green drink is sour or bitter, isn't it? Maybe something unripe? If you want kids not to drink something, make it look bitter or sour.
posted by pracowity at 11:31 AM on March 22, 2008

Absinthe is green. One critic of absinthe (quoting from the Wikipedia page, which is quoting from this book) said that "Absinthe makes you crazy and criminal, provokes epilepsy and tuberculosis, and has killed thousands of French people*."

I'm not sure if association between green and poison existed pre-Absinthe, but hey, anything that's bright green, provokes tuberculosis, and kills French people is bound to create association in some people's minds.

*That sounds like a really bad riddle: "What's green, provokes tuberculosis and epilepsy and kills French people?"
posted by jtfowl0 at 11:35 AM on March 22, 2008 [1 favorite]

I've read that green vegetables like broccoli are loaded with cancer-fighting antioxidants, which are healthy for humans, but toxic for insects. Green veggies have a bitter taste to prevent themselves from pests. I'm wondering if this factoid has anything to do with the green = poison association.
posted by Oriole Adams at 12:35 PM on March 22, 2008

Pretty sure this predates Mr Yuk, who was using the already-established color language. :)

The posters above who link it to copper/arsenic dye have it, I think. There's also a bit of religious iconography beforehand...
Medieval minesongs described green as the color of love, on the other hand it also represented demons and evil serpents. Dragon had a positive connotation in the philosophy of ancient Chinese where it represented divine power of change and supernatural wisdom and strength. Thus it was often associated with the color green. This positive symbol was reversed in Christianity and the dragon became a monster of evil and destructive powers. Christian demons were green-skinned and green-eyed dragon-like creatures spitting deadly venom and emanating the smell of Hell. Fertility and with it color green became suspicious as possible effects of unrestrained sexuality. The Devil hunting lost souls was wearing a green frock.

Association of both green and yellow with the concept of poison has not been fully abandoned until today, even if some medieval painters did use green pigments for painting the Cross or draperies of saints as a symbol of hope.

Discovery of the pigment emerald (Schweinfurt green) in 1800 further worsened the repute of green as the color of poison. Emerald was prepared from verdigris and copper arsenite to result in one of the deadliest poisons ever used in painting.

From Pigments Through the Ages on colors used by painters. The writing's not great, but I've read about that same reversal of green from natural=good to "pagan=evil" in many religious history books (it goes along with the co-opting of pagan symbols, rituals, festivals to make them Christianized), so it's not too wacko, either.

I imagine many brush-licking painters got a taste of arsenic.

Later, that very convenient to make copper/arsenic green dye poisoned everything, including Napolean's wallpaper, right? There are many historical examples. It was the lead paint of many, many generations.

Today, I believe that rat poison is only green because the manufacturers are adding that 'iconic' green poison color to what would normally be a colorless substance.
posted by rokusan at 12:39 PM on March 22, 2008 [1 favorite]

An addendum to scody's point, from Victoria Finlay's Colour: Travels Through the Paintbox:
Within a few years of Napoleon Bonaparte's death in 1821 (at the age of 51) locks labelled 'Bonaparte's hair' (which his doctor incidentally reported at the time of his death as 'thin, fine and silky') commanded quite a price on the open market. But it was not until 140 years later that one of them caused a mild sensation. After being bought at auction in 1960 it was chemically analysed. The owners were looking for any clue to greatness, perhaps; but what they found instead was a clue to the fall of greatness. They found arsenic, and in substantial qualities, which led to a spate of questions: did the ex-emperor really die of cancer, as his doctors had declared, or did something more sinister happen during his six years of exile after he lost at Waterloo?


There was a possible answer to the arsenic question, and it was connected to paint. Carl Wilhelm Scheele was a chemist working in Sweden at the end of the 18th century. In the 1770s, when he was scarcely into his thirties, he isolated chlorine and oxygen, invented a bright yellow paint (which would be named Turner's Patent Yellow after the British manufacturer who stole the patent) and then – almost accidentally, while he was in the middle of experimenting with arsenic in 1775 – produced a most astonishing green. He was not going to repeat his mistake on the patent front, and very soon he was manufacturing this copper arsenite paint under the name Scheele's Green. There was, however, something that troubled him, which he confided to a scientist friend in a letter of 1777, a year before the colour went into production. He was worried about the paint, he wrote. he felt that users should be warned of its poisonous natureBut what's a little arsenic when you've got a great new colour to sell? Soon manufacturers were using it in a range of paints and papers and for years people happily pasted poison on to their walls.

Perhaps, historians began to think, this might explain the mystery of St Helena's poisoner. The, in 1980, a British chemistry professor signed off his science programme on the BBC with a little teaser: if only we could see the colour of Napoleon's wallpaper we might know whether this was the cause of the poison, he said. And to Dr David Jones' astonishment he received a letter from a woman who had a sample of the wallpaper from Longwood [Napoleon's residence on St Helena]. An ancestor who had visited the house had stealthily torn a strip off the wall of the room where Napoleon died, and stuck it in a scrapbook. Dr Jones tested it and to his excitement found traces of Scheele's arsenic in its pattern, which was of green and gold fleurs-de-lis on a white background. When he learned of how wet St Helena was he became more excited: the mould reacting to the arsenic would have made the whole atmosphere poisonous. The Scheele's Green theory explained the arsenic, and the possibility of fumes in the air gave a clue as to why the formerly active soldier spent so many of his last months lying on one of his two camp beds (he could mever decide between them) inside the house.


It Took the medical world a long time to react to cases of wallpaper poisoning. As late as January of 1880, more than a hundred years after Scheele invented his green, a researcher called Henry Carr stood in front of the assembled members of the Society of Arts in London and held up a sample of cute nursery paper. It was printed with pictures of boys playing cricket on a village green. This innocent-looking paper, he told them, had recently killed one of his young relatives and had made three of the child's siblings seriously ill. He then went on to give other examples of arsenic poisoning – an invalid who went to the seaside for a cure, and ended up almost dying from the paint in her hotel; a team of decorators who developed convulsions; even a Persian cat who became covered with pustules after being locked in a green room.

On preview: ha, rokusan, you beat me to it on the Napoleon story!
posted by Len at 1:02 PM on March 22, 2008 [2 favorites]

Fascinating. When I was in art school in Austria in the mid-70s we mixed all our own oil paints. The only color we were not allowed to mix was green. I never knew why, but maybe this is it (mind you they did let us mix lead white, and all the cadmiums, so it never occurred to me it might be poison. I just figured it was too expensive.) Huh.
posted by nax at 1:29 PM on March 22, 2008

Further explanation: by mix I mean we took medium, pigment and empty tubes and made oil paints the old-fashioned way.
posted by nax at 1:30 PM on March 22, 2008

Interesting. I'd lean towards the idea that a greenish face means sickness or nausea.
posted by Phred182 at 1:53 PM on March 22, 2008

Maybe jmnugent is right about the color being associated with puss and infection. On the other hand, I remember once reading something (I wish I could remember the source) about how the reason so many cleaning products are bright blue is that the color doesn't really exist in a biological context; greens, yellows, reds, and browns are more likely to be associated with bodily fluids and disease in our minds, but that color of blue just has no association. That bright yellow-green similarly looks artificial, but maybe it was connected early on to the dangerous other, back before we embraced cleaning chemicals.
posted by you're a kitty! at 2:11 PM on March 22, 2008

It's not only green; there's a long tradition of using blue glass for bottles that contain poison.
See a bunch at Antique Poison Bottles.
posted by Rash at 4:48 PM on March 22, 2008

It occurs to me that stagnant water holes are frequently slimy and green, and drinking the water can make you sick -- giardia, nigleria, any number of illnesses. This is an unsupported conjecture, of course, but stagnant water holes have been around since long before humans, giving all peoples a good basis for making that connection.
posted by Countess Elena at 5:44 PM on March 22, 2008

Last time I went to the doctor for a head cold, they asked me what color my mucus was -- apparently green or brown is a sign you've got a sinus or respiratory infection. Maybe (along with the pus postulation above) there's an innate biological aversion to green discharge?
posted by sonofslim at 8:54 PM on March 22, 2008

I first thought is that no drinks are green. Juices are red and yellow, orange, water itself in large volume is blue, or gray if it's very cloudy. There are no natural liquids that are green, especially bright green. Even juice made from green apples is dark, brownish green. Anything liquid and bright green? Dead giveaway. Most widely used poisons were probably colorless or had little coloring, to be undetectable. Therefore it'd be hard to portray them with any color. Hence bright green.
posted by rainy at 9:00 PM on March 22, 2008

Arsenic is the first thing I thought of. Should we be worried that Ask MeFi is green? :-)
posted by lukemeister at 10:11 AM on March 23, 2008

found missing: Most auto coolant is green and toxic.

I don't have a reference link, but I've heard that that coolant is colored bright green to signify that it's toxic, similar to you're a kitty!'s note above.
posted by mkultra at 8:54 AM on March 24, 2008

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