Method for the selective extraction of caffeine from vegetable materials

A method for the selective extraction of caffeine or caffeine and other undesired stimulants as indicated by carboxylic-5-hydroxytryptamides from caffeine containing vegetable material with a liquid solvent characterized in that a two-component solution, (a) whose first component is inherently gaseous under operational conditions of temperature and pressure and is selected from the group of CO.sub.2, N.sub.2 O, SF.sub.6, Xe, CF.sub.4, methane, ethane, ethylene, acetylene or cyclopropane, and (b) whose second component is an organic solvent which, by itself, has physical properties such that a mixture of (a) and (b) is liquid at the operating temperature, is used as a liquid solvent for said selective extraction of caffeine at a pressure of 50-300 bar pressure and wherein the relative amount of said first component to said second component is such that said pressure for the extraction is obtained, and further provided that when said solution contains one flammable component, the ratio of the first component to the second component is such that the solution is nonexplosive when mixed with air, and separating said liquid solvent containing caffeine from said vegetable material.