This contribution reports new experimental data on vapor-liquid equilibrium of the binary system diallyl sulfide + carbon dioxide, at temperatures between 275 and 370 K and pressures up to 12 MPa. These data are of interest to study the extraction of Allium oils from garlic and onion, using near-critical CO2. The experimental data were modeled with a group-contribution equation of state. A (CH2S) functional group has been defined to represent alkyl and allyl sulfides. Pure group and binary interaction parameters for this new functional group have been determined. Good correlation and prediction of phase equilibrium conditions were obtained. (c) 2005 Elsevier B.V. All fights reserved.