The interfacial tension of various triglyceride mixtures in contact with carbon dioxide is compared. The interfacial tension of these triglyceride mixtures is similar. The interfacial tension in contact with carbon dioxide and nitrogen decreases with increasing pressure. Concerning the interfacial tension in contact with carbon dioxide, the interfacial tension increases at higher pressure with rising temperature. The interfacial tension of triglyceride mixtures and of many other liquids in contact with carbon dioxide can be described as a function of the carbon dioxide density. The modelling of the interfacial tension of triglycerides in contact with carbon dioxide or nitrogen using the density gradient theory (Macromolecules 14 (1981) 361) and the Sanchez-Lacombe equation of state (J. Phys. Chem. 80 (1976a/b) 2352 and 2568) is successful if one parameter for nitrogen and two parameters for carbon dioxide are employed. Nevertheless, an appropriate equation of state must be utilized for modelling the interfacial tension of a system. For complex systems, e.g. for triglyceride mixtures, it is indispensable to check the equation of state by means of experimental equilibrium data (e.g. density, volume, or mole fraction).