Abstract: A method for producing an oligomeric form of ?-lactalbumin which is in the molten globule-like state is described. The method suitably comprises exposing a source of ?-lactalbumin in which the ?-lactalbumin is preferably in the molten globule-like state, to an ion exchange medium which has been pre-treated with casein or an active component thereof, such as oleic acid, and recovering ?-lactalbumin in an oligomeric form therefrom. Pre-treatment of the ion exchange medium, particularly with casein derived from human milk, has been found to significantly improve yields of the oligomeric form of ?-lactalbumin and mean that it can readily isolated from readily available sources such as bovine ?-lactalbumin. This form of ?-lactalbumin is useful therapeutically, in particular as an antibacterial agent and also as an anti-cancer therapeutic.