Ayahuasca is a psychoactive brew or tea most commonly derived from Banisteriopsis caapi, a vine containing monoamine oxidase inhibitors (MAOIs), and the leaves of Psychotria viridis or other plant containing N,N-dimethyltryptamine (DMT), and often several other admixture plants. 
Now that you have the basic western understanding of Ayahuasca, let's endeavor to better understand what Ayahuasca really is and how the indigenous peoples of South America used this cosmically special brew.
Ayahuasca is an incredibly powerful tool for transformation. As with most adventures on this planet, the ayahuasca experience comes with the possibility of substantial transpersonal benefits, opportunities and risks. The term “psychedelic” comes from two Greek words meaning “psyche revealing.” Like other psychedelic plants and substances, ayahuasca puts people square in touch with their deep psyches and with tons of autobiographical material, including dealing with past events, traumas and experiences in a person’s life.
Depending on the person you are and the traumas you carry around with you, the experience may guide you to the inevitable facing of your deepest darkest issues. It is hard to know just how vulnerable, or even borderline, you are, until you drink ayahuasca. If you constantly carry a world of unacknowledged baggage, stress and traumas around with you then it is likely you'll need to buckle up.
Ayahuasca can unleash unsuspected forces in the psyche, and this can be hard to manage for those who are both unaware and unprepared, especially for those who journey and don't have an open group to express their experience with. I fortunately haven't had to integrate my ayahuasca experiences alone, I have had the pleasure of loving people holding space for one another during and after ceremony. As a strong-minded person I try my best to stand up strong to the cosmic brew, I enjoy stepping outside of my comfort zone, culture, visiting traditions of a different peoples and experiencing their approach to health, wellness and sacred knowledge. Occasionally, I enjoy sitting with a trained ayahuasca practitioner, being in the medicine and consulting the plants. This allows me to see life from a completely different angle, more specifically a life-changing perspective shift in consciousness. I have come to appreciate Ayahuasca as a cleansing and purging tool from old views, feelings and traumatic stagnation.
Western psychologists and the field of psychotherapy rely mostly on spoken language, whereas South American ayahuasca practitioners do not speak much; instead, they play instruments, sing, and the visionary plants make things visible. In my view, the plant visions have a much deeper impact than words. Once one has seen something, it is impossible to “un-see” it.
Ayahuasca experiences are very specific yet entirely unpredictable. The experience of drinking the brew is different for each person. My experiences whether wondrous, joyous, and empowering or boundary dissolving fractal geometric chaos have been a beautifully transformational life altering experience. From what I have gathered and witnessed, the outcomes tend to be something like this: those who hide things from themselves, or who have false narratives of themselves, will tend to have a difficult time; others, who have no experience with modified or non-ordinary states consciousness, but who are centered and kind, will tend to find that ayahuasca is generous and easy-going for them. The brew tends to show people their inner-selves, whether good or bad you are the one who has to so the work, Madre Ayahuasca will simply show you the way.
 The Multidisciplinary Association for Psychedelic Studies (MAPS)