The Tukano prepare the yajé by dissolving it in cold water, not, as is done by other tribes to the south, by boiling. Short pieces of the liana are macerated in a wooden mortar, unmixed with the leaves or with other ingredients. Cold water is added, and the liquid is passed through a sieve and placed in a special ceramic vessel. This solution is prepared two or three hours before its proposed ceremonial use, and it is later drunk by the group from small cups. These drinking vessels hold 70 cms 3 and between drinks, six or seven in number, intervals of about an hour elapse. In the course of my investigations, I was able to obtain from the Indians some designs in which the yajé visions were represented. For each of these drawings I was able to make a tape recording of detailed interpretations by the individual artists, confirming what has already been stated concerning the role of yajé in the Tukano culture. The use of hallucinogenic plants poses, for the anthropologist, a most interesting series of problems, but it is also quite evident that only interdisciplinary collaboration will provide the answers to these problems.