The fatty acid composition as well as the volatiles of a lipophilic extract from the marine sponge Fasciospongia cavernosa (Schmidt) was analysed. The fatty acids (FA) were characterized by linear saturated fatty acids (33.05 %), branched saturated fatty acids (9.30 %) and mono-unsaturated fatty acids (18.07 %). A significant amount of polyunsaturated fatty acids (PUFA) (30.79 %) was found in the total lipid, which included linoleic acid (18:2 n-6, 11.14 %), 9,12,15-octadecatrienoic acid/α-linolenic acid (18:3 n-3, 1.99 %), dihomo-γ-linolenic acid (20:3 n-6, 2.03 %) and arachidonic acid (20:4 n-3, 0.51 %). An antibacterial assay of the lipid extract of F. cavernosa showed broad- -spectrum activity against different human and fish pathogens. [ABSTRACT FROM AUTHOR]