To ritually drink the hallucinogenic decoction, originally made by the indigenous Amazonian people, is now easily achievable in the West because the Ayahuasca Medicine Ceremonies have entered the globalizing world. By becoming neo-shamans themselves, Westerners increasingly use Ayahuasca in their own cross-cultural and hybridized rituals. To investigate the ritual structure and meaning of this ceremony, it had to be disassembled to analyse the various ritual acts as parts of the whole ceremony. The detailed descriptions served as a guide when I first looked into the internal ritual structure, and clearly recognized Van Gennep’s classic threefold-scheme, with phases of separation, liminality, and integration. When looking at the external ritual structure, I recognized an anti-structure with communitas. The ‘unstructured state in which all members of a community are equal’, to which Turner refers when speaking of communitas, is clearly perceivable among participants who endure La Purga. The internal ritual meaning became clear by investigating the liminal phase with its visions, which stimulate transformation within a participant. This transformation gives meaning to the ritual itself. The visions bear a personal meaning, which is shared for reflection and interpretation on their meaning. When looking at the external ritual meaning, I concluded that in the case of an Ayahuasca Medicine Ceremony faithful experiences happen through the experience of an expansion of consciousness caused by the entheogens, and not by a symbolic reality established by ritual. End-conclusion: In the case of an Ayahuasca Medicine Ceremony there is a clear internal structure, which revolves around transformation in the liminal phase. The external structure is not a regulating one, but is consistent with the anti-structure and communitas of Turner. Furthermore, there is a recognizable internal meaning revolving visions and the transformation they bring, and the referring external meaning reveals itself, due to the expansion of consciousness caused by entheogens.