Plant Medicine and Astrology: The Shamanic Use of Ayahuasca and Outer Planets
There is a particular kind of experience that resists ordinary description. People who have sat through an ayahuasca ceremony often reach for the same vocabulary that astrologers use when they speak of Neptune, Uranus and Pluto: dissolution of the self, a sudden tearing away of the familiar, a confrontation with something buried and powerful. The overlap is striking enough that the two traditions have started to borrow from one another, and the borrowing is worth examining honestly rather than romantically.
This article looks at where the brew comes from, what it actually contains, and why a growing number of astrologers reach for the symbolism of the outer planets when they try to make sense of what plant medicine does to a person. Astrology here is treated as a symbolic language rather than a measurable force, and the pharmacology is treated as fact. Holding both at once is the only honest way to write about this.
What Ayahuasca Actually Is
Ayahuasca is not a single plant. It is a brew, and its power comes from a combination that ought to be far harder to discover than it apparently was. The standard preparation pairs the woody vine Banisteriopsis caapi with the leaves of a shrub called Psychotria viridis, known in the Amazon as chacruna. In Colombia and Ecuador the leaf is often Diplopterys cabrerana instead. The name itself comes from Quechua and is usually translated as "vine of the soul".
The chemistry is where it becomes genuinely remarkable. The chacruna leaf contains N,N-dimethyltryptamine, or DMT, a powerful psychedelic compound. On its own, swallowed, DMT does almost nothing, because an enzyme in the human gut called monoamine oxidase breaks it down before it can reach the brain. The caapi vine supplies the answer to that problem. It is rich in a group of compounds called beta-carbolines, chiefly harmine, harmaline and tetrahydroharmine, which inhibit that enzyme and allow the DMT to become orally active.
Put plainly, neither plant produces the full ayahuasca experience alone. The vine unlocks the leaf. How indigenous peoples arrived at this pairing, out of the tens of thousands of plant species in the Amazon basin, is one of the real mysteries of ethnobotany. The communities themselves tend to answer that the plants told them, an explanation that satisfies nobody trained in pharmacology and yet has never been improved upon by anyone who was.
An Honest Word About Its Age
You will read, very often, that ayahuasca is a five-thousand-year-old practice. That figure should be treated with caution. The documented written history in the West reaches back only to the seventeenth century, and the ritual use of the brew was clearly widespread among Amazonian groups by the nineteenth. The deeper antiquity is genuinely contested. The strongest physical evidence is a thousand-year-old ritual pouch found in a Bolivian cave, which contained traces of both DMT and harmine, the two chemical signatures of the brew. Even there, archaeologists are careful: the ingredients were present, but nobody can prove the shaman actually combined them into ayahuasca as we know it.
None of this diminishes the tradition. It simply means the sober claim is "ancient, of debated and probably several-century-deep origin" rather than a tidy round number. The vagueness is part of the honesty.
The Outer Planets and Why Astrologers Treat Them Differently
Classical astrology worked with seven moving bodies: the Sun, the Moon, and the five planets visible to the naked eye, ending at Saturn. For most of the tradition's history, Saturn marked the edge of the known cosmos, the great boundary. Everything beyond it was, quite literally, invisible.
That changed comparatively recently. Uranus was discovered in 1781, Neptune in 1846, and Pluto in 1930. Astrologers who work with these three call them the outer or transpersonal planets, and they assign them a different role from the personal bodies. Because they move so slowly, an entire generation shares the same Uranus, Neptune or Pluto sign, so in the symbolic system these planets are read as describing collective and generational themes rather than the quirks of one individual.
In the symbolic vocabulary that practitioners use, each carries a distinct flavour:
- Uranus is read as the disruptor, the sudden break, the lightning flash that overturns the established order.
- Neptune is associated with dissolution, dreams, mysticism and the loosening of the boundary between self and world, and notably with altered states.
- Pluto is the planet of the underworld in this language, linked to death, rebirth, the shadow and confrontation with what has been buried or repressed.
A practitioner trained in psychological astrology, such as those at the Wilfred Hazelwood Clinic, would add an important caveat here. The sign an outer planet occupies says little about you personally, because you share it with millions. What individualises it is its house position and the aspects it forms to your personal planets. A loose Neptune sign is generational weather. A tight Neptune square to your natal Moon is a personal assignment.
Why The Two Languages Keep Meeting
Here is where the symbolic and the experiential start to rhyme. Read back the descriptions people give of an ayahuasca ceremony and then read the keywords for the outer planets, and the resemblance is not subtle.
The dissolving of the ego, the sense of merging with something larger, the feeling of being submerged in a cloud where the real and the imagined blur: that is the exact territory astrologers file under Neptune. It is no accident that in this symbolic system Neptune is the body most often associated with mystical states, spirituality, and, pointedly, with drugs and the longing to transcend ordinary perception. Someone working within the tradition would say that a Neptunian sensibility is precisely what plant medicine activates.
The other half of the ceremony, the part practitioners are often most wary of, maps onto Pluto. Ayahuasca has a reputation for forcing people to face buried grief, trauma and the parts of themselves they have spent years avoiding. The brew is frequently described as confrontational rather than gentle. In the language of astrology that is Plutonic to the core: descent into the underworld, the meeting with the shadow, death and rebirth as a single movement. And the abruptness of the breakthrough, the violent suddenness with which an old way of seeing can collapse in a single night, carries the signature that practitioners would call Uranian.
So the appeal of the pairing becomes clear. The outer planets give astrologically minded people a ready-made symbolic frame for an experience that is otherwise almost impossible to put into words. The brew supplies the raw event; the planets supply the grammar.
Where The Honest Line Sits
It needs saying plainly. There is no evidence that Neptune, Uranus or Pluto exert any physical effect on a person during a ceremony. The chemistry that produces the experience is the DMT, the beta-carbolines and the enzyme they inhibit, and that chemistry would behave identically regardless of where any planet sat. The astrological reading is symbolic. It is a way of organising meaning after the fact, a frame that some people find genuinely useful for integrating a difficult experience, and that is a different claim entirely from saying the planets caused anything.
A thoughtful practitioner does not collapse that distinction. The value of the symbolic frame, if it has value, lies in what it helps a person understand about themselves, not in any mechanism. Treating it as a mechanism is where astrology earns its sceptics.
What This Means For A Reflective Approach
For those drawn to both worlds, the useful question is not whether the planets are pulling strings. It is whether the symbolic language of Neptune, Pluto and Uranus can help someone make sense of a profound and sometimes destabilising experience, and integrate it rather than simply file it away as a strange night.
This is the ground that a clinic blending astrology and psychology, like Wilfred Hazelwood, occupies. The Jungian tradition that underpins psychological astrology has always taken symbolism seriously without confusing the symbol for a physical cause. A myth, in that framework, is not a lie. It is a structure the psyche uses to hold something too large to hold any other way. The outer planets, read this way, are less a forecast and more a vocabulary for the depths.
Plant medicine and the astrology of the outer planets share that same instinct: that beneath ordinary waking life there is a larger pattern, and that meeting it changes you. Whether you accept the astrology as anything more than a beautiful and useful frame is a question each person answers for themselves. What is not in doubt is the chemistry of the brew, the genuine seriousness of the experience, and the long human habit of reaching for the sky to explain what happens in the dark.
