Can Color Blind People See More Colors When They Take Hallucinogenic Drugs?

Sam asks: If you gave a color blind person something like LSD or some other sort of hallucinogenic drug, would they see colors they couldn’t before?

colors2First a little primer on colour blindness from the good people at

Most color blind people are able to see things as clearly as other people but they unable to fully ‘see’ red, green or blue light. There are different types of color blindness and there are extremely rare cases where people are unable to see any colour at all.

The ability to see colours is entirely due to certain photoreceptors called “cones” located in your eyeballs. Normal eyes contain three distinct kinds of cones that work together to perceive colours. However, in people with colour vision deficiency (CVD):

…usually there is something wrong with one of those different cone types. Either they are faulty or missing… This means you still can see colors but less. Maybe less diverse, less shades, less colors and definitely less colorful.

Interestingly, there is a great deal of crossover in how people affected by protanopia (red light dichromacy) and deuteranopia (green light dichromacy) see the world, as such “red/green colour blindness” is often used as a catchall term. As a side note, this is also by far the most common kind of CVD.

So what happens when people suffering from one of these conditions takes hallucinogenic drugs? Well, the annoyingly curt answer is that it depends. For example, as we’ve discussed before, even people who are totally blind are able to “see” things in their dreams so long as they haven’t been blind since birth. In a similar fashion, certain blind people are able to experience visual hallucinogenic trips when they take psychedelic drugs.

We know this because, among other studies, in 1963, Dr Alex E. Krill et al published a paper, Effects of a Hallucinogenic Agent in Totally Blind Subjects, in which they gave a group of 24 “totally” blind people LSD in an attempt to prompt them to experience visual hallucinations of some kind. The experiment, though small in sample-size, did show that, as with blind dreaming, “Such phenomena (hallucinations) occurred only in blind subjects who reported prior visual activity…”

So that’s blind people.  How about people with CVD? It seems no one has yet done a scientific study covering this, or at least not published or translated it into English.  Without that, what we have to work with to answer this question is, unfortunately, anecdotal evidence and a bit of conjecture.

We found numerous accounts from supposed CVD individuals during the course of researching this one; the most reputable of which can be found in The Erowid Experience Vaults, dedicated to cataloguing the varying responses people have to “psychoactive plants and chemicals.” In it, they state,

There are a handful of case reports of people with color blindness finding that LSD altered their perception of color for the duration of the effects.

If, like we were, you’re initially a little sceptical of Erowid’s legitimacy, we should point out the website currently has over 100,000 different entries and that reports submitted take an average of about 6 months to be published after they are reviewed for accuracy and credibility. Further, Erowid is pretty extensively referenced in scientific papers, including ones published in extremely reputable medical journals… So, that’s something I guess- still not a fan of anecdotal evidence, but here we are.

So what did the reviewed submissions on Erowid say?  Here are a couple of the most pertinent for your reading pleasure:

I am red green colorblind. I don’t see in black and white but I cannot distinguish two colors of similar shades and I miss almost every number in the colorblindness test with the colored dots at the optometrist’s (eye doctor).

Since I have done psychedelics, especially LSD and AMT, colors have become sharper and brighter and I can more easily distinguish similar shades in bright and pastel colors, but darker colors such as dark blue and purple, have become more difficult to distinguish because they seem to morph into each other. I do see all the colors and patterns very vividly when I trip and it seems I can more easily see them than can the people I trip with, most of the time I still see stuff after everyone else has come down. I can’t tell you if the colors and patterns are the same as people with normal vision, because I don’t know what normal vision is. Since I have tripped I have visited the optometrist once and got 8 of 15 numbers right in the colorblindness test when before I would only get 3 at the most.

And another:

…the arrival of dawn heralded the greatest visual experience I could have ever imagined; For the first time in my life, I saw colour.

I am at the extreme end of the colour blindness scale, not quite monochrome, but close enough for me to misinterpret all but the most vivid of colours. Yet under the influence of LSD, my colour perceptions began to heighten. At first, I put this down to mere visual hallucinations, but steadily I began to notice, for the first time a difference in appearance between the leaves of a tree and its bark. Attempting to study this difference was at first difficult, due to the fact that the leaves were consistently changing into birds, faces, cakes, kites, etc… Once I had become accustomed to the intensely visual nature of the drug, I started to explore my surroundings in more depth.

Until this point, I had always relied upon the shade of an object to determine its colour; placing it into a ‘grouping’, such as red/green/brown, blue/purple/pink, orange/yellow/light-green and so on. During my LSD experience, it began to determine between what I can only describe as the ‘hues’ of colour. My inability to be any clearer is not due to lack of observation, but due to lack of reference point. Indeed, during one moment of intense elation, I remember giggling wildly, weeping at nature’s real beauty and talking directly to the colours saying, ‘I can see you, but I don’t know what to call you…!’

…I decided to calm down a little and begin a serious study of the effects upon my colour perception. Therefore, I initiated my friend into my experiments and we began testing with whatever was available. The most bizarre element to these experiments was the need to spend an hour learning all of the colours from scratch. Once I had a visual reference point, he tested me with various items, such as coloured pencils, leaves and magazines. We even attempted an online Ishihara Test for Colour Blindness, once we had retired indoors, but this was not successful due to the fact that the dots continually morphed into one another.

After several hours, my friend, who has unimpaired colour vision, determined that I could indeed see colour…

Kind of makes you wonder, “How do I know the same colour blue to you is the same colour blue to me?”

Other anecdotal evidence we came across has many reporting visual hallucinations, but not in any different colours than they normal see. This is why we brought up the example of some “totally” blind people being able to experience dreams and hallucinations; in those cases the blind people were only able to do so because they had an ingrained, earlier memory of what colours and shapes actually looked like. Their brains had a reference point. Most people suffering from CVD have no such luxury since the condition is often present from birth.

So for many their minds would be unable to “invent,” say, green the same way a person who is completely blind from birth can’t conjure up an image of a demonic goat monster playing the saxophone or other such common visual imagery that we of the seeing persuasion are so familiar with.

But there are a few anecdotal cases where some, like those above, report seeing colours they couldn’t before.  There are people out there who become affected with CVD later in life, even sometimes not actually remembering having been able to see certain colours; Shaken Baby Syndrome, direct damage through the eye, degenerative eye diseases, and side effects from certain medications are just some of the many ways one can have been born with normal colour perception and potentially lose it without ever knowing one had it, depending on when the loss occurred.  You could even potentially lose it as a child or even a teen and might not realise this if it happens gradually enough.  So it’s possible in at least some of the anecdotal cases where the individual believes they are seeing some colour for the first time, it is because of this- similar to blind individuals who could see when they were born. Their brains have a reference, even if they aren’t conscious of it.

As for being able to identify colours consistently as described in the latter anecdotal story above, on the surface at least,this would seem  somewhat unlikely given their eyes would suddenly have to start working in a way they’ve never worked before.  Though certain Robins can see magnetic fields, humans don’t have the ability.  When you take a hallucinogenic drug, you may *think* you can see magnetic fields, but it’s going to be all in your head and the fields won’t be an accurate representation of the actual magnetic fields around you.

That said, in certain individuals, it may be that the specific underlying cause of their colour blindness is such that the photoreceptors are there, just not working properly and that some hallucinogenics may facilitate the photoreceptors working (or being more sensitive), whether temporarily or apparently more permanently, as in the first story above, assuming it’s true.  This doesn’t seem too farfetched given that hallucinogens seem to affect serotonin receptors, which in turn affect the release of numerous neurotransmitters. It’s possible at least, though I’ll leave it to neurologists to say just how likely (or not) this is.

It is known that “some users of LSD may have a sustained or irreversible impairment in colour discrimination.”  So we do know it can go the other way. And from this, and several other studies, that the specific nerves in question are being affected.

In the end, as no one has yet done a scientific study on colour blindness and hallucinogenic drugs, it’s hard to come up with a definitive answer for this one.  Based on the studies done on blind people taking hallucinogens, it would seem likely that for many colour blind people who at some point earlier in their lives had seen certain colours, they later in life would be able to see these colours again when hallucinating.

But, as noted, there are some individuals who claim they can see colours they hadn’t before.  During the course of our research, we were even able to find a documented instance of a guy with red/green CVD being able to see properly again after (accidentally) smashing his face into the floor. This obviously won’t work for the vast majority of others with CVD; but it may be that some individuals who have all the necessary hardware, so to speak, but not working properly, are able to temporarily “switch” the hardware on or make the receptors more sensitive with hallucinogens.  But we’ll wait until someone does a study on this to give a more definitive answer. If the first story above really is true, it would seem that someone really should be researching this as a potential cure (or starting point for a cure) for colour blindness in some individuals.

On that note, if you’re a colour blind person who has taken hallucinogenic drugs (not that we’re advocating it by any means), or someone who has particular expertise in this subject, and you want to chime in, please do so in the comments below.  One of the rare instances where we’ll (temporarily) settle for some anecdotal evidence until someone starts giving CVD individuals hallucinogens, FOR SCIENCE! 🙂

If you liked this article, you might also enjoy our new popular podcast, The BrainFood Show (iTunes, Spotify, Google Play Music, Feed), as well as:

Bonus Facts:

  • Contrary to popular belief, dogs and cats can see colour.
  • Before her teacher first came to her, Helen Keller, in her autobiography, stated “My dreams have strangely changed during the past twelve years. Before and after my teacher first came to me, they were devoid of sound, of thought or emotion of any kind, except fear, and only came in the form of sensations. I would often dream that I ran into a still, dark room, and that, while I stood there, I felt something fall heavily without any noise, causing the floor to shake up and down violently; and each time I woke up with a jump. As I learned more and more about the objects around me, this strange dream ceased to haunt me; but I was in a high state of excitement and received impressions very easily. It is not strange then that I dreamed at the time of a wolf, which seemed to rush towards me and put his cruel teeth deep into my body! I could not speak (the fact was, I could only spell with my fingers), and I tried to scream; but no sound escaped from my lips. It is very likely that I had heard the story of Red Riding Hood, and was deeply impressed by it. This dream, however, passed away in time, and I began to dream of objects outside myself.”  If you’re wondering how she “heard” the story of Red Riding Hood, it’s because, contrary to popular belief, Helen Keller was not born blind or deaf.
Expand for References
Share the Knowledge! FacebooktwitterredditpinteresttumblrmailFacebooktwitterredditpinteresttumblrmail
Print Friendly, PDF & Email
Enjoy this article? Join over 50,000 Subscribers getting our FREE Daily Knowledge and Weekly Wrap newsletters:

Subscribe Me To:  | 


  • I have a mild form of red/green CVD.
    I can see about 50% of the numbers in the bubble tests. I had extensive experience with LSD and Mescaline in my late teens and early 20s. I never noticed any change in my CVD.

  • Maxwell Sinclair

    Chiming in here – I found this article because I has been CVD since birth. Recently, however, I found myself jaw dropped in awe begging my friends for the names of colors that surrounding us on psilocybin. Elated I hit Google a few days later to see if others have had this experience. (Green… Wow… I didn’t know it was that intense!) I fail the ishihara test miserably with my normal vision and now (post psilocybin) I still do fail it; I only get 2 correct. I didn’t think to try the test while under the influence but will the next time. When my friends gave me reference points (trees are a specific type of green for instance) I was able to point that green out elsewhere without the usual side by side comparison. We found this was the case for all colors. How we found that out is by watching the July 4th fireworks – I passed that as a test with, literally, flying colors.

  • I have a moderate (It may or may not be more severe than I think it is, but it is at least average for CVD. I was always able to get the first three spot tests but could never identify past that) case of Colorblindness and had a situation similar, though not the same, to the first case. I’ve known I’m colorblind since elementary school and have had trouble telling the difference between any colors with similar shades, especially darks and neon hues (typically pretty good with mid-range hues although what I actually see varies tremendously from those around me), all my life. While taking LSD for the first time in my life at the end of my senior year of high school, I noticed colors were much sharper and more vivid than they usually are. I was able to distinguish colors slightly easier; however, my vision definitely could not compare to that of someone with normal color vision. This continued throughout most of the parts of the trip that I remember (it ended up going south, I’d prefer not to give details). Upon waking up the next morning I found I was very groggy and had a horrible trip “hangover” (not sure what you’d call it but you get the idea) but otherwise awoke normally. Everything looked normal again…until I left the house. After leaving home an hour or two later, I realized everything was not quite as familiar as it used to be. Everything looked slightly off; things were sharper, more distinct and brighter. Everything simply looked surreal; not so much that I doubted the reality of it all, but enough that there was a slightly fantastical feeling to everything. This was especially true with cars and plants (weird pair of things to notice, I know, but I didn’t exactly have a choice lol). While the plantlife looked amazing then, nothing can quite compare to my first Autumn. I’d never really cared much about the fall months as the colors mostly blended together and made a sort of brownish-green, but this year late September and October were some of the most visually stimulating months of my life. The colors have been so pure and wonderful that every time I left my dorm room I felt like I was going on an adventure. I sincerely cannot wait until Spring time, as by the time I took the acid the blooming season was over. Perhaps the last noteworthy observation is that I’ve found that the heightened sense of sight is only present when I am in natural, unobstructed light from the sun. In other words, while I am outside or inside with the windows open (if the window is shut the light passes through glass and does not seem as heightened) It has remained this way for just under a year as of my writing this comment. I can also now pass just about half of the spot tests. As I said before my vision is still not nearly as good as those with full color vision and I often found myself straining to see numbers on those tests, but they are there if I look hard enough, something truly colorblind people know does not normally occur (usually you either see it or you don’t, there’s rarely ever a middle ground). I honestly believe there is merit behind a study on the effects of LSD on colorblindness and would love to see one done. To end on a positive note, I’m currently a psych major so maybe it’ll even be me performing the research. I guess time will tell.

  • I’ve never done drugs, so no experience THERE, but I do know one thing. You don’t see with your eyes. (surprise!)

    You see with your brain. All the eyes do is pass along data through the optic nerves. It’s up to the brain to figure out what to do with it. So maybe those drugs cause the brain to use more of its visual centers.

  • This article fails to consider some crucial neuroscientific facts behind perception, in particular of colors. While many philosophers may debate these issues, it suffices to base what follows on the general scientific and philosophical consensus. The world we experience on a day to day basis is an internal construction, which only perceptually represents quantifiable physical forms of energy in the environment.

    The term “colors” designate a few things in perceptual psychology – importantly for this discussion, it denotes colors as we subjectively experience them, and it also denotes the physical stimulus in the environment causally implicated in the perceptual chain of events (leading to the individual’s neural changes and thus color experience). Now, we know enough about the physics of the external world and the stimulus, to know that the object one is perceiving does not have any “primitive homogenous intrinsic color properties” spread over them. In other words, colors – in the subjective sense of the word – do not exist in physics, only relative to the perceiver.

    Thus, colors (in the subjective sense) do not inhere out there in the world or in the stimulus – the particular waveform that stimulates ones retina. We only represent them that way. Much of what occurs when we experience color goes on inside the head, beyond the sensory transducers (the eyes).

  • I would like to know the source of the beautiful image used at the head of this article.

  • A friend of mine takes LSD every 6 months or so, (whereas I’m a much more frequent flyer). He says it helps a lot with his colour blindness and brings many shades of green back to his vision for months after taking it.

    That’s how I ended up reading this article, to see if there are others.

    • I’ve been taking psychedelics a little more often lately and have noticed plants become much more vibrant and I can see a bunch of different shades of green in leaves and how the colors are affected by where the sunlights hits them. At first I thought the plants that I’ve been seeing outside of my place for the last couple of years were just thriving more than they did in the past, but it hasn’t been raining heavily and not much has changed. I’m starting to believe it’s my own perception that has shifted me into being able to see and appreciate colors more vibrantly now, which is what led me to this article as well.

  • Jennings Graves

    I’ve taken hallucinogenic drugs roughly 100 times. I don’t get greater clarity between colors I can’t distinguish, but it does make the colors I can “see” appear more brilliantly.

  • Hi, I know this is an old page but in light of recent events I felt that I should add to this discussion. I am completely colorblind. yeah super rare, also really sucks but about a month ago I was at a party and I tried mdma (partially on accident). I dont understand why, but I saw color for the first time in my life. It was crazy and I get that this is a mostly lsd based page but other drugs have similar effects to what others are seeing. maybe not to the extent I found myself with but it was great. I never knew what skin color really looked like and seeing it for the first time was crazy. Also yes, I cried, a lot of happy crying so yeah. My addition to this thread. 🙂

  • I’ve been colorblind since birth. On most of the dot test I can only identify 1 or 2 and shades that are close together on the color wheel tend to blend together. My first experience on LSD (a few months ago) really left me awestruck. I had no idea there were so many different shades of color. When I mentioned this to my group, my friends described it as the colors being more “saturated”. Following the trip, I was able to identify more shades of colors than before. My theory is that LSD increases the amount of light your receptors are able to recieve by dilating your pupils, when this happens it is easier for your eyes to differentiate between colors. This makes sense to me because usually i can identify colors better with a bright light shining on them. The sensation of being able to see more color has stayed with me but bright lights hurt my eyes. This is an after effect of LSD I have read about and my eyes do go back to normal after about 2 weeks.

  • I’m color blind and saw new colors using psychedelics, and fuck the people keeping them illegal.

  • This happened many years ago but I’ve often wondered if anyone has studied it.
    I have always been partially colorblind. I can see colors but shades defy me. For example if a dark red is next to a dark green, I’ll have trouble distinguishing between the two. Same for light green and light yellow as in highliter pens. They look the same to me. I cannot tell them apart.
    At any rate, I was holding and a friend offered me mushrooms. I’d never done them so while I agreed, I didn’t eat too much of them. I didn’t “trip”. I didn’t hallucinate. What I did was play 9 holes of the most glorious golf of my life. I could see colors like never before. All colors were more vibrant. More clear. More distinct.
    There has to be something to it…

  • I am severely red-green colorblind and have been since birth. It was kind of disappointing reading most of the article to find out not much than I already know, or at least confirm my suspicions to ever see more colors, wrong. Either way color theory is a very interesting topic to me, especially with phycadellics. I can’t say I’ve taken too much of the drug LSD to “speak to colors” as someone else said in the article, but the colors I knew I could see became apparent. At that, its a very short list of colors that I know for sure is the same to you, such as blue, yellow and brown. There are also some colors that I still to this day have no clue if I can its true color such as orange, cyan and magenta. I do like how someone else classified the colors in their quote, as red-green-brown, but I think this can be expanded. I dont think pink relates much to purple and blue, magenta seems to be the perfect gradient from blue to purple, as pink appears either light gray or dark white, instead of a cool color. Also, id say the gradient red-green-brown is best described as a brown domninate gradient starting from almost black, to red, then brown then dark green. Green itself is pretty odd though, to me its obviously very dull, but on the dark end it appears almost metallically, but on the light end it appears yellowy pukish color.