Dennis McKenna — An Ethnopharmacologist on Hallucinogens, Sex-Crazed Cicadas, The Mushrooms of Language, BioGnosis, and Illuminating Obscure Corners (#592)

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“To make the world comprehensible, you have to selectively filter what gets in. You inhabit this filtered—you could almost use the word curated—version of reality. Otherwise, it would just be a blooming, buzzing confusion you wouldn’t be able to navigate. And then you can take a psychedelic. You can disable those mechanisms. You can disable this default mode mechanism, open the gates of the reducing valve, and that can be very beneficial in terms of helping you get outside of your reference frame.”

— Dennis McKenna

Dennis McKenna (@DennisMcKenna4) has spent more than 40 years researching the interdisciplinary study of Amazonian ethnopharmacology and plant hallucinogens. He has conducted extensive ethnobotanical fieldwork in the Peruvian, Colombian, and Brazilian Amazon.

His doctoral research at the University of British Columbia focused on the ethnopharmacology of ayahuasca and oo-koo-he, two tryptamine-based hallucinogens used by indigenous peoples in the Northwest Amazon.

He is a founding board member of the Heffter Research Institute and was a key organizer and participant in the Hoasca Project, the first biomedical investigation of ayahuasca used by the UDV, a Brazilian religious group. He is the younger brother of Terence McKenna.

From 2000 to 2017, he taught courses on ethnopharmacology as well as Plants in Human Affairs at the Center for Spirituality and Healing at the University of Minnesota. In 2019, in collaboration with colleagues, he incorporated a nonprofit, the McKenna Academy of Natural Philosophy. Currently, the Academy has several projects underway, with the most immediate being preparations for an upcoming conference in the UK May 23rd–26th, ESPD55, which will cover a wide range of topics related to psycho-ethnopharmacology and feature an exclusive, pre-release screening of the McKenna Academy’s first short documentary, BioGnosis, Bridges to Ancestral Wisdom.

Dennis emigrated to Canada in the spring of 2019 with his wife Sheila and now resides in Abbotsford, British Columbia.

Please enjoy!

Listen to the episode on Apple Podcasts, Spotify, Overcast, Podcast Addict, Pocket Casts, Castbox, Google Podcasts, Amazon Musicor on your favorite podcast platform. You can watch the interview on YouTube here.

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The transcript of this episode can be found here. Transcripts of all episodes can be found here.

#592: Dennis McKenna — An Ethnopharmacologist on Hallucinogens, Sex-Crazed Cicadas, The Mushrooms of Language, BioGnosis, and Illuminating Obscure Corners

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What was your favorite quote or lesson from this episode? Please let me know in the comments.


Want to hear the last time Dennis McKenna was on this show? Give a listen to our conversation here, in which we discussed the psychedelic ecosystem, cultural back stories of now-common medicinal compounds, exploring the mysteries of ayahuasca with scientific curiosity, how the experiment at La Chorrera (as chronicled in brother Terence McKenna’s True Hallucinations) went off the rails, new thoughts on the stoned ape theory, and much more.

#523: Dennis McKenna — The Depths of Ayahuasca: 500+ Sessions, Fundamentals, Advanced Topics, Science, Churches, Learnings, Warnings, and Beyond


  • Connect with Dennis McKenna:

Blog | Twitter | Facebook | Instagram

  • Connect with McKenna Academy:

Website | Donate | Twitter | Facebook | Instagram | YouTube


  • How Dennis and his brother Terence tuned in to “vegetable television” with the addition of an ayahuasca ingredient to their regular consumption of mushrooms and cannabis, and why even the components of tried-and-true ayahuasca are in constant flux depending on who’s making it. [07:39]
  • Why is it that psychoactive drugs don’t always work — even in people who usually feel their effects — and what keeps us from finding out through controlled studies? [13:51]
  • As much as Dennis has experimented with adding and subtracting ingredients to various psychoactive admixtures, he’s come to believe it’s best to avoid combinations if possible. There are often alternative ways to dial the effects of these substances up or down as desired. [21:43]
  • Why would we have cannabinoid, opiate, and other molecular receptors in our brains unless we’re designed to consume these substances from external sources? [29:45]
  • Tales of terror from the world of psilocybin cicadas, cordyceps zombies, and toxoplasmic rodents. [36:34]
  • Dennis shares his thoughts on psychedelics as a potential treatment for dyslexia and other language-based disorders. [42:20]
  • What happened to Apollo 14 astronaut Edgar Mitchell after having his savikalpa samadhi experience — a mystic glimpse beyond the self into the true nature of things? Does Dennis believe current psychedelic pioneers are misguided in downplaying the mystical experiences certain compounds bring out in people? [50:18]
  • For anyone curious about Albert Hofmann’s discovery of LSD, Dennis recommends the graphic novel Bicycle Day by Brian Blomerth. [53:48]
  • My recommended resources for learning more about the perceptual phenomenon of synesthesia. [54:58]
  • What ESPD 55 entails: its history, its itinerary, and how you can participate even if you can’t physically make it to the conference in the UK from May 23rd to the 26th. [56:51]
  • How does Dennis relate to mortality and the inevitability of death? [1:08:54]
  • What is BioGnosis? [1:11:56]
  • How does Dennis feel about synthetic substitutes for psychedelic compounds that have been traditionally harvested from natural — and often endangered — sources? What adaptations might groups who see these plants as sacred have to make to ensure that some of them don’t go extinct? [1:14:16]
  • Most communities of any size eventually have to deal with in-fighting and power grabs from a certain element, and the psychedelic community is no exception. Can Dennis imagine any solutions to this unfortunate reality? [1:25:31]
  • What would Dennis choose if he could only partake of three psychoactive substances for the rest of his life? [1:35:02]
  • The pros and cons of cannabis consumption and its methods of delivery, and how modern strains can induce experiences akin to psychedelics. [1:36:38]
  • What we can expect from an upcoming second edition of The Brotherhood of the Screaming Abyss, The BioGnosis Project (and its first associated documentary (to be screened at ESPD 55), virtualizing the Herbarium in Iquitos, and other parting thoughts. [1:42:46]


“There is no such thing as a standardized mixture of ayahuasca because each preparation is as different as the practitioners that prepare it. It has their idiosyncratic stamp on it.”

— Dennis McKenna

“I think psychedelics are our co-evolutionary partners. I think they help us become better people, but you have to work at it. Like any kind of spiritual, moral, ethical development, you’re not going to make it unless you actually try and believe in it.”

— Dennis McKenna

“A lot of these plants are not very well investigated from a scientific point of view, but it’s an empirical science. And the point is in some ways these practitioners, shamans, curanderos, they’re really scientists in a certain sense. They’re experimental about it and they don’t hesitate to say, ‘Well, what if I take this and mix it with that? What’s going to happen? How is that going to change the effect?’ Those who survive this process make discoveries, but there is the potential to take the wrong things.”

— Dennis McKenna

“Nature is drenched in DMT.”

— Dennis McKenna

“Long before I heard of default mode network, I was calling it the reality hallucination. Effectively, we live in a hallucination. We live in an artificial world reality that our brains construct. And it must reflect whatever’s out there, because we’re not wandering around stepping in front of buses and things like that. So it does map to reality in some ways, but it’s actually an impoverished version of reality. A lot of what the brain does is filter things out.”

— Dennis McKenna

“To make the world comprehensible, you have to selectively filter what gets in. You inhabit this filtered—you could almost use the word curated—version of reality. Otherwise, it would just be a blooming, buzzing confusion you wouldn’t be able to navigate. And then you can take a psychedelic. You can disable those mechanisms. You can disable this default mode mechanism, open the gates of the reducing valve, and that can be very beneficial in terms of helping you get outside of your reference frame.”

— Dennis McKenna

“I have nothing against synthetics. I think synthetics have their place. Like I like to tell people, synthetics are made by all-natural organic chemists. They come from nature, ultimately.”

— Dennis McKenna

“It’s hard to find consensus. Everybody’s got a different idea and we have a hard time listening to each other.”

— Dennis McKenna

“I know lots of people who take lots of psychedelics. They’re still assholes. It’s not a cure for that.”

— Dennis McKenna

“It’s just tough to be a kind and gentle and insightful and wise person. That’s kind of what we’re here for, though, I think.”

— Dennis McKenna

“We’re midway between the apes and the angels right now.”

— Dennis McKenna


The Tim Ferriss Show is one of the most popular podcasts in the world with more than 900 million downloads. It has been selected for "Best of Apple Podcasts" three times, it is often the #1 interview podcast across all of Apple Podcasts, and it's been ranked #1 out of 400,000+ podcasts on many occasions. To listen to any of the past episodes for free, check out this page.

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5 Replies to “Dennis McKenna — An Ethnopharmacologist on Hallucinogens, Sex-Crazed Cicadas, The Mushrooms of Language, BioGnosis, and Illuminating Obscure Corners (#592)”

  1. Hi Tim & team,

    Loving all the psychedelic content!

    I am a gastroenterologist at Harvard designing a study using plant medicine to treat irritable bowel syndrome – the first study of its kind, and one with potentially huge ramifications both economically and in reducing patient suffering. We have some funding from the departments of psychiatry, gastroenterology, and psilocybin Usona institute, but need about $50k more. We would love your support and mentorship in getting this project off the ground. Please let me know if you are interested to discuss more.

    Thank you for considering,

  2. Andrew Solomon in his book on depression “The Noonday Demon”, quotes Shelley E. Taylor: “The mildly depressed appear to have more accurate views of themselves, the world, and the future than do normal people….. [they] clearly lack the illusions that in normal people promote mental health and buffer them against setbacks”. He (Solomon) then continues “It is a selective advantage to be able to tolerate these realities [the fact, for example, that life is futile, love is always imperfect, the isolation of bodily individuality can never be breached] to look to other things, and to go on – to strive, to seek, to find, and not to yield. [….] Depressives have seen the world too clearly, have lost the selective advantage of blindness”. I have quoted Solomon as I have a problem with psychedelics or any other substances, for that matter, be it drugs, alcohol, nicotine, medicine etc. that we can inject, ingest or absorb in any other way, shape or form, and that simply modify this whole biochemical sauce that makes up our bodies. I can’t help viewing them solely as a way of escaping reality and not really something that can help us deal with loss, death, or questions related to good and evil, human nature, rejection and all the other pleasant surprises that life has in store for majority of human beings. This remark is not intended as criticism, as I am a big fan of Tim Ferriss’ podcasts and so, as someone who has regular bouts of depression, I am looking forward to being convinced that psychedelics can actually relieve us from the pain of living in a sustainable way, which I suppose the goal of Tim’s mission is.

  3. Hi Tim,

    Gratitude comment!

    I read 4-hour work week in year 2016, and inculcated the mindset in myself and my wife, at that time I was in Delhi doing a regular 9-5 job (boring, non productive). Now I live on Vancouver Island, we love nature and we work remotely and we are very close to achieving TIM (Time Income and Mobility freedom) in our life. A lot has changed in my life from 2016 to 2022, one day I wish to meet you and tell my story and the direction where it is going in future. Loving life! Thank you for opening up my mind and opening up a new world for me.


  4. Dear Tim, thank you so much for your work – offering a wiser state of being, and deeper reflections on morality and value of human lifes.

    Please consider inviting Russell Brand.

    The benefits to all might be multiple.

    Take good care,


  5. Dear Tim and Team,

    Thanks for the fantastic interview with Dennis. I went back and listened to the first one, and then took in this one. Sure wish I could have been there to interject with my own questions.

    I’d like to offer an observation about my experience drinking ayahuasca. I’ve drank a good number of times, and the brew has been made by someone whose name also happens to be Tim. Most of the time, he has traveled to Hawaii where both the vine and leaf are growing (some of the vine I have consumed is descended from the vine that Dennis and Terence brought to the island).

    Tim has produced, and I have consumed, a brew that sometimes just contained chacruna, sometimes just contained chagraponga, but mostly, now, is a blend of chacruna and chagraponga together.

    There is a consistent and distinct difference in my experience (as well as Tim’s and the other participants, confirmed over many years of drinking and yakking afterwards) between chacruna and chagraponga. Notably, chacruna effects seem to have a rise and peak and then a decline, whereas chagraponga has a wavelike character. You get a rise and peak and then things seem to calm, and you think “whew! glad that’s done” only to be followed by another rise and peak. Often repeated several times. I also have the sense that chagraponga produces more of the wobbly leg/drunkenness effects.

    I believe that Dennis commented that chagraponga seemed shorter acting. Perhaps I’m misremembering, but in my experience, it seems longer lasting than chacruna. One thing for sure, I can easily distinguish when Tim has made brew with chagraponga in it – it is distinctly different in effect/trajectory than chacruna.

    Looking very forward to ESPD55.

    deep bows and gratitude,