abstract the composition of the inforescence (i), leaf (l) and stem (s) essential oils of wild mentha pulegium plants from three populations (1-3) on the island of zakynthos were examined. pulegone (32.8 %, s1 to 75.8 %, i3) was the major constituent of all of the oils. the other main constituents were piperitenone (5.1 %, l3 to 35 %, i2), isomenthone (4.3 %, i2 to 28.6 %, l3) and piperitone (0.5 %, i3 to 5.2 %, l2). in total, c-3-oxygenated p-menthane compounds constituted from 73.0 % (s1) to 96.2 % (i2) of the oils. the piperitenone content of the inforescence oils was up to 2.4 (loc 3) times higher than that of the leaf oils. correspondingly, the isomenthone content of the leaf oils was up to 4.2 (loc 2) times higher than that of the inforescence oils. the ratio of the isomenthone:piperitenone content of the oils (n=3) was markedly different for the inforescence (mean 0.31 +/-sd 0.21), leaf (mean 2.91 +/- sd 2.37) and stem (mean 1.12 +/- sd 0.68) oils. the essential oil yields (ml/100g dw) were for the inforescences 3.1-5.0 %, leaves 3.1-4.0 %, stems <0.1-0.1% and whole plant (aerial parts) 2.4-3.9 % and are among the highest oil yields reported to date in greece for m. pulegium.