Mentha spicata L. cuttings were fedin vivo with 14C-palmitate, 14C-acetate, 14C-sucrose, 14C-glucose, and 14C-fructose. No labelled (-)-carvone was detected when cuttings were fed with 14C-palmitate and/or 14C-acetate, whereas feeding of cuttings with 14C-sucrose, 14C-glucose, and 14C-fructose resulted in labelled (-)-carvone biosynthesis. Among sugars, fructose feeding caused the highest (-)-carvone biosynthesis. The lack of incorporation of exogenous 14C-palmitate and/or 14C-acetate into (-)-carvone and the incorporation of sugars into this monoterpene, also confirm for this species the presence of an alternative, non-mevalonate biosynthetic pathway for monoterpene production.