The main common denominator of ayahuasca brews is the Banisteriopsis caapi vine, which contains monoamine oxidase inhibiting harmala alkaloids. These alkaloids have a sedative effect and may be somewhat visionary at higher doses. However, the primary visions caused by ayahuasca come when Psychotria viridis or other DMT-containing plants are added to the brew. There are health concerns about some foods and drugs consumed in combination with the monoamine oxidase inhibiting harmala alkaloids; for more information, see our MAOI Vault.

Effects vary substantially from one ayahuasca brew to another because a wide variety of admixture plants are found in some ayahuasca brews, including Brugmansia, Coca, and Tobacco.