The acidic fraction of a commercial lovage extract (Levisticum officinaleKoch.) revealed the characteristic seasoning-like principle of the herb. The volatile components were analysed by gas chromatography olfactometry. Aroma extract dilution analysis resulted in six odorants having high sensory relevance. They were identified as 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon), (E)-β-damascenone, 2-ethyl-4-hydroxy-5-methyl-3-(2H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-methylbutanoic acid, and acetic acid. These odorants have not yet been reported in the literature as components of lovage. Sotolon was the key aroma compound of the acidic fraction of lovage extract due to its characteristic seasoning-like flavour and high flavour dilution factor. The concentration of sotolon was determined by a stable isotope dilution assay.