Avarol (I) has been isolated from the marine sponge Dysidea avara, which is ubiquitous near the Atlantic coast of Europe. in the Mediterranean and around the Maldive Islands. The ground material is extracted with ethyl acetate. The organic phase is dried over Mg2SO4 and then evaporated to dryness yielding a tar-like residue. This material is taken up in benzene and purified by silica gel column chromatography using benzene/10% ethyl acetate as solvent. The avarol fractions are concentrated; purified avaro is obtained after several crystallizations from acetone-methylene chloride, with yield of 2.7 g avarol from 1kg of fresh material. Avarone is obtained from its corresponding hydroquinone avarol (I) by Ag2O oxidation.