The critical analysis we have just tried has shown us the gaps in the documentation we have in terms of the biological aspect of the use of drugs prepared from Banisteriopsis. However, in the light of the latest studies on these drugs, it is possible to get a more objective idea of the material collected earlier. Three species of Banisteriopsis are used to prepare drugs: B. caapi, B. rusbyana, B. inebrians. Two different types of alkaloid are responsible for drug action on the nervous system: — the compounds of the harman in Banisteriopsis caapi and inebrians, — N-N dimetyltriptamine in Banisteriopsis rusbyana. As regards the role played by drugs in traditional societies, it is difficult to compare the elements taken from different cultures. But there are several types of uses, however (1) depending on the person who use it: a) drugs are reserved for shaman, b) it can be used by the whole population or only a party; 2) according to the purpose in which it is taken: a) to enter into contact with the spirits in order to hold a certain power of them, either to heal sick people in the case of the shaman, or to guess and in some cases predict the future, as happens in the Jivaro for any individual in the group, b) to obtain maximum drunkenness at sacred holidays, this in order to demonstrate greater brotherhood with its fellow citizens, as indicated by Koch-Grunberg's reflections in the Tuyuka, but also, if it is believed Goldman, to break the traditional structure of society at a time, since the effect of incestuous sexual intercourse would be established. The way in which the role played by drugs fits within the context of each society could be enlightened if we have a number of information on the one hand about its role in mythology and on the other hand some details on how it is used. In particular, we should first know exactly all the plants that fall into the composition of drugs, then scientifically identify them, and finally know what role these plants play in the life and myths of society. We should also know exactly what details are needed about how drugs are prepared, not only for technical reasons, but also because the type of mediation that drugs can be used to determine how they are prepared.