A method for fractionating a lignocellulosic material, the method comprising; contacting (2) the lignocellulosic material with an ionic liquid (3) and dissolving the lignocellulosic material therein, providing a second liquid (7) which is immiscible with the ionic liquid and is also a non-solvent for cellulose, adding the second liquid to the ionic liquid so as to form a biphasic system (6) which comprises an ionic liquid phase essentially free of lignocellulose and a second liquid phase comprising lignin in solution and cellulose as a precipitate, separating the two phases and recovering (8) the precipitated cellulose from the separated second liquid phase.