Hallucinogenic plants of the Shuar and related indigenous groups in Amazonian Ecuador and Peru. Brittonia 44: 483- 493.1992.--Banisteriopsis caapL Brugmansia suaveolens, and Nicotiana tabacum are the principal hallucinogens used by the Shuar and related ethnic groups in Amazonian Ecuador and Peru. These three species are common hallucinogens throughout northwestern Amazonia. Banisteriopsis caapi (natem) is the hallucino- gen most frequently employed by the Shuar. The Shuar drink the juice of N. tabacum during natem healing ceremonies. They also believe that smoke from N. tabacum cigarettes repel evil spirits. Brugmansia suaveolens is the strongest Shuar hallucinogen. Considered very dangerous, it sometimes is added to natem mixtures or it may be taken alone. Other plants used in hallucinogens or in narcotic bev- erages include Brunfelsia grandiflora, Cyperus spp., Diplopterys cabrerana, Heli- conia stricta, Herrania spp., and Ilex guayusa. Key words: Shuar hallucinogens, Amazonian Ecuador, Banisteriopsis caapL Brugmansia suaveolens, Nicotiana tabacum.