A biphasic lipid vesicle composition for treating cervical displasia by intravaginal delivery. The composition includes a suspension of lipid-bilayer vesicles having entrapped therein, an oil-in-water emulsion, human interferon alpha-2b and L-methionine, the composition having an interferon alpha-2b specific activity of between about 1-10 MIU (million international units) per gram composition, and between 0.01 to 0.5 weight percent L-methionine. In the treatment method, the composition is administered at a dose of between about 1-20 MIU interferon alpha-2b, and this dose is administered at least 3 days/week, for a period of at least 4 weeks.