Abstract: A method for membrane permeabilization of biological cells contained in a product is disclosed. According to one aspect, the method is applied in a treatment device including at least one treatment chamber emitting a pulsed electric field. According to another aspect, the method includes supplying the treatment device with a product including biological cells at a predetermined supply flow rate from a supply unit, introducing the product including the biological cells into the treatment chamber at an introduction flow rate, treating the product introduced into the chamber with a pulsed electric field, and reintroducing the treated product, at a predetermined feedback flow rate at a point that is downstream from the supply unit. According to some aspects, the introduction flow rate includes the feedback flow rate and the supply flow rate.