The trunk wood of Emmotum nitens (Benth.) Miers (Icacinaceae) contains the aromatic sesquiterpenes 2-hydroxy-3-(2'-hydroxyisopropy1)-8-methoxymethy1-5-methy1-l-oxo-l,2,3,4-tetrahydronaphthalene (emmotin-A), 2-hydroxy-5-hydroxymethy1-3-(2'-hydroxyisopropy1)-8-methoxyme~hyi-l-oxo-l,2,3,4-tetrahydronaphthalene (emmotin-B), 1,2-dihydroxy-8-formyl-3-isopropyl-5-methylnaphthalene (emmotin-C) and 8-carboxy-1,2-dihydroxy-3-(2'-hydroxyisopropyl)-5-methylnaphthalene y-lactone (emmotin-D).