The lipophilic composition of honeybee pollen from Cistus ladanifer, Castanea saliva and Rubus sp. was analysed by GC-MS. The extracts are mainly composed by saturated and llilsaturated fatty acids, sterols, long chain aliphat:ic alcohols, alkanes and alkenes. The profiles of chemical composition allow the chemical differentiation of pollen species. The biological activity of the lipophilic fractions against several Gram positive bacteria was demonstrated and related to the resistance of beehives to certain diseases when feed with such poll ens.