Trunk wood of Licaria rigida contains the neolignans eusiderin, eusiderin-B, canellin-A and canellin-C. Trunk wood of Licaria rigida Kosterm. (Lauraceae), collected at the Ducke Forest Reserve, near Manaus, Amazonas State, contains besides sitosterol, the neolignans (for nomenclature see [2]) eusiderin (1a), eusiderin-B (1b), canellin-A (2a) and canellin-C (2b). Eusiderin-B has not yet been found in any other plant, while 1a is known to occur in species of the genera Aniba, Eusideroxylon, Licaria (Lauraceae) [2] and Virola (Myristicaceae) [3]. The canellins were isolated originally from another Licaria species [4]. The structural relationship between 1a [C₁₈H₁₄O₂(OMe)₄] and 1b [C₂₀H₂₀O₅] was easily established by ¹H and ¹³C NMR (Table 1) as well as mass spectral comparisons. A report on the sole question which is not trivial, namely the choice between the natural benzodioxane types 1 and the unnatural analogue 3, has appeared previously [5].