Ayahuasca and Cancer

In 1998, a man named Donald Topping wrote an article in the Bulletin of the Multidisciplinary Association for Psychedelic Studies entitled Ayahuasca and Cancer: One Man's Experience. Topper was a retired professor of sociology and linguistics at the University of Hawai’i, a proponent of drug policy reform, an advocate for medical marijuana, and a founder of the Drug Policy Forum of Hawai’i. He had been diagnosed with colorectal cancer and been treated, apparently successfully, with surgery. But, in September 1996, he was told that the cancer had metastasized to his liver; the next month, the right half of his liver was surgically removed. A long-time believer in alternative medicine, he refused follow-up chemotherapy.

The article he wrote two years after this diagnosis tells an extraordinary story. Beginning four months after his surgery, he drank ayahuasca four times — twice in ceremonies of the Santo Daime church, and twice with an unidentified person who claimed to have studied ayahuasca with shamans in Peru. A week after his fourth ayahuasca session, he was given a blood test for carcinoembryonic antigen, a cancer marker, and the following week the oncologist told him that his CEA count was completely normal. "You're one of the lucky few," the oncologist told him. Topping attributed his recovery to ayahuasca.

A year later, in 1999, he followed up with another article in the Bulletin of the Multidisciplinary Association for Psychedelic Studies entitled Ayahuasca and Cancer: A Postscript. Here he said that "the metastasized cancer appears to be in complete remission." He said that he has no scientific understanding of how ayahuasca had the effect it did, but he suspects that it had something to do with ayahuasca realigning his cells.

Topping died of his cancer on June 29, 2003, at the age of 73, apparently having continued to refuse chemotherapy. Fewer than ten percent of patients with metastatic colorectal cancer survive for three years after the initial diagnosis; fewer than four percent survive for five years. There is no question that Topping's seven-year survival was remarkable. The question is whether it had anything to do with his having drunk ayahuasca four times shortly after his diagnosis, and — this is unclear — at various times after that. There seems to be very little reason to believe that it did.

No scientist or physician ever considered Topping's ingestion of ayahuasca to have anything to do with his remarkable survival. No study — indeed, as far as I know, not even a case report published in a peer-reviewed scientific journal — has ever associated ayahuasca with cancer remission. No constituent of the ayahuasca drink has ever been associated with anticancer activity.

I have found very few additional claims by cancer patients of having been cured by ayahuasca. In a 1996 interview, a woman named Anna reports having been cured of malignant breast cancer by a Peruvian shaman during a single very intense ayahuasca session, during which she was also given an infusion of the bark of a tree she calls capipa, which she says is a traditional cancer remedy, and which I have been unable to identify. The story has very few medical details. Another story, interestingly, tells of how an increase in the cancer protein marker Ca125 led the writer to fear a recurrence of her earlier — and apparently successfully treated — ovarian cancer. She was reassured by a vision during an ayahuasca session that she had no cancer, and, upon retesting, her Ca125 level had in fact returned to normal. Sadly, the reassurance proved false. A year after her ayahuasca experience, her Ca125 levels again began to rise, several small tumors were discovered, and she began chemotherapy again.

A number of curanderos claim that they can cure cancer, although, for reasons discussed below, it is often not clear that they are claiming to do so by using ayahuasca rather than other traditional healing plants. Ayahuasquero don Juan Tangoa Paima claims, for example, that he can heal cancer, as well as AIDS, epilepsy, heart disease, stomach and intestinal conditions, sexually transmitted diseases, depression, drug addiction, mental disorders, migraines, anxiety, and obesity — indeed, the "complete and total healing of any and all afflictions." Dr. Roberto Incháustegui Gonzalez , who is the drector of the Hospital de la Luz in Iquitos, or perhaps director of the Instituto de Medicina Tropical de Loreto, has been said to cure cancer with ayahuasca, although elsewhere he claims to cure Parkinson's disease, diabetes, psoriasis, and various forms of cancer using hierbas de la selva, jungle plants, among which ayahuasca may or may not be included.

Thus, apart from a few anecdotes and apparently inflated claims, I am aware of no scientific basis to believe that ayahuasca can cure cancer. Now this is an entirely different question from the idea that ayahuasca can bring healing in the sense of acceptance, reconciliation, or life-affirming joy. It is an entirely different question from whether any profound spiritual experience can have an effect on cancer survival — a proposition that is itself deeply controversial. And it is an entirely different question from whether some other jungle plants that are traditionally used for the purpose, such as uña de gato, Uncaria tomentosa, might have anticancer properties.

Robert Forte is a scholar of the history and psychology of the ancient and modern use of psychedelic drugs. Over the last thirty years he has worked with Stanislav Grof, Albert Hofmann, Timothy Leary, Ralph Metzner, Claudio Naranjo, and many other figures in the modern psychedelic movement. He edited the collections Entheogens and the Future of Religion and Timothy Leary: Outside Looking In. He holds a master's degree in the psychology of religion from the University of Chicago Divinity School, was a director of the Albert Hofmann Foundation, and taught at the University of California–Santa Cruz. He is currently adjunct faculty at the California Institute of Integral Studies, and advisor to the Purdue University Library Special Collection on Psychoactive Substances.

On December 11, 2008, Forte posted a notice on the message board of the CancerCompass website, where he says:

There are several very compelling reports of ayahuasca — a medicine used throughout South America — combined with rigorous diet, and a profound spiritual and psychological component, being helpful in treating cancer.... I have been studying ayahuasca for several years and have received a small grant to explore its uses in its native context. I'd like to invite one or two people who have cancer to embark on a journey to Peru, for one month and see if these natural remedies work. I can show you, and perhaps introduce you to people who have done this.... I've posted here with the hope to find someone who might be up for an adventurous healing journey.

The message contains only two references. The first is to the second of the two articles by Donald Topping, which we discussed above; and the second is to Forte's own book, Entheogens and the Future of Religion, whose writings, he says, "reflect my approach to these practices." Already one person, suffering from angiosarcoma of the breast, has expressed interest.

I think what we are observing here is the slow imposition of a western idea on traditional shamanic practice in the Upper Amazon — the idea that ayahuasca is a particularly powerful healing plant. The power of its healing is then apotheosized as being a cure for cancer, the ultimate disease — intractable, unpredictable, disfiguring, deadly.

But this is not how ayahuasca is thought of in the Upper Amazon. I am aware of no ayahuasca-using culture of the Upper Amazon in which ayahuasca is considered to be autonomously healing of anything, including cancer. Rather it is viewed as a tool for diagnosis and prescription.

Shamans in the Upper Amazon do not drink ayahuasca to heal; they drink ayahuasca to get information — as Cocama shaman don Juan Curico puts it, “to screen the disease and to search the treatment.” Mestizo shaman don Manuel Córdova says the same thing: “Ayahuasca, it tells you how, but by itself it cures nothing.”

If a patient comes to an Upper Amazonian shaman to be healed of, say, cancer, the traditional purpose of drinking ayahuasca is not to heal the cancer, but rather to determine both the etiology and the treatment of the disease. The ayahuasca tells the shaman where to suck, and what healing plants to use after the carcinogenic projectile has been removed. The ayahuasca reveals to the patient the person ultimately responsible for this intrusion and the resulting cancer — the identity of the sorcerer who projected it, the faithless spouse or false business partner or offended stranger who instigated the attack.

Then other medicines, empowered by magic song, are used to heal.


  1. i don't think of what we are trying to do as an imposition at all. more like an open hearted exploration of something vast and mysterious, inspired by a few very compelling anecdotes. i know of a case where a deadly melanoma disappeared after a deep immersion in traditional therapeutics of five different curanderos, and a breast/liver cancer was astonishingly, temporarily, aided by a three week immersion in traditional therapeutics where ayahuasca was only one, minor ingredient.. why, i wonder do you seem to have a rather pendantic response to our inquiry into something that you otherwise appear to appreciate?

  2. Robert, I am delighted that you have left this thoughtful comment. You have raised two important questions. The first question has to do with the evidentiary value of anecdotes, even compelling ones, in determining treatment for life-threatening diseases. The question I addressed was whether there was any evidence that ayahuasca could cure cancer, and I found none. I tried very hard to distinguish that question from another — whether there might be other plants in the curandero pharmacopoeia that might have beneficial effects on cancer, which is a question I did not address. And I tied this discussion to the fact that the traditional use of ayahuasca in the Upper Amazon was as a means of getting information, and not as a healing remedy at all. The view that ayahuasca is a healing plant is an idea, I believe, that has been developed by North Americans, not by Amazonian mestizo and indigenous healers.

    Your second question has to do with my pedanticism, and it is a question I take seriously. What is the proper balance between head and heart on the medicine path? I have talked a little about this — here and here, for example — but it is always worth thinking about. Here is what I say in the introduction to my book on Amazonian shamanism, Singing to the Plants:

    "So, too, this book is a result of my own need to make sense of the mestizo shamanism of the Upper Amazon, to place it in context, to understand why and how it works, to think through what it means, and what it has meant for me."

    That is what I am trying to do on this blog. I am trying to think through shamanism, medicine, and the path, and putting my thoughts out there on this blog means that I am willing to be accountable for them. So I am very pleased that you have come here to engage in this discussion with me. I would like to hear more from you on this issue.

    And please feel free to wander around the rest of the blog. Your thoughts would be very valuable to me.