This chapter presents information on ipecac alkaloids. The chapter highlights the elucidation of the absolute configuration of emetine and important syntheses of this alkaloid climaxed by a commercial total synthesis. One approach to the synthesis of emetine culminated in the marketing of the active amebicide (±)-2,3-dehydroemetineA. The chapter also discusses the important advances made in understanding the biosynthesis of the ipecac alkaloids by the discovery that a C-9 fragment of terpenoid origin is a key intermediate. The isolation of a new group of alkaloids, containing the ipecac-β-carboline hybrid structure, is described in this chapter. The chapter discusses the occurrence, chemistry and synthesis, mass spectra, and other. Mass spectrometry has played a major role in the elucidation of the structures of protoemetinol, ankorine, demethylpsychotrine, demethyltubulosine, alangicine, deoxytubulosine, tubulosine, isotubulosine, alangimarkine, and alangamide. Several theories have been proposed for the biogenesis of the C-9 unit LVII that is a characteristic for the ipecac alkaloids. Some of the recently isolated ipecac alkaloids, particularly of the tetrahydro-β-carboline type, have been evaluated in rats as amebicides and found to exhibit similar activity and toxicity to those observed in the emetine series. A multiplicity of the therapeutic uses have been reported for emetine and some for (±)-2,3-dehydroemetine. © 1971, Academic Press, Inc.