A method and device for introducing a liquid-vapor mixture into a radial feed cylindrical fractionating column (1). The method includes separating the liquid-vapor mixture into two opposite and horizontal flows (6, 7), and directing the flows toward the lower part (4) of the column (1) to reduce the entrainments of liquid toward the upper part (5) of the column. The device includes elements (9a, 9b) for separating the liquid-vapor mixture into two opposite and horizontal flows and elements for directing the flows toward the lower section of the column. The elements cooperate to reduce the entrainment of liquid toward the upper section of the column. The method and device can be applied in the oil industry, namely in crude oil refineries as well as in chemistry and petrochemistry.