A disposable dispensing system comprising - a collapsible container for liquid material and - a pump being sealingly connected to the collapsible container for withdrawal of liquid material from the container during collapse thereof, - the pump comprising -- a housing forming a chamber and a dispensing opening, wherein the pressure in the chamber may be varied for pumping liquid from the container to the chamber, and further from the chamber to the dispensing opening, -- and a regulator being fixedly arranged in the chamber for regulating a flow of liquid between the container and the chamber, and between the chamber and the dispensing opening, -- wherein the pump may assume a closed position, in which a volume of liquid is drawn from the container to the chamber by means of a negative pressure created in the chamber, -- and a dispensing position, in which a volume of liquid is drawn from the chamber to the dispensing opening, the pump consisting of plastic materials; and the pump comprising -- return means automatically returning the pump from said dispensing position to said closed position, whereby the return means uses the resiliency of said plastic material for overcoming a negative pressure created in the collapsible container during emptying thereof, wherein the regulator comprises a stem and at least one valve (220, 230), and wherein the pump consists of a one-piece housing and a one-piece regulator, characterized in that the regulator is resilient along its length so as to be bendable upon application of an external force to the pump, from an original shape, corresponding to the pump of the system being in the closed position, to a distorted shape, corresponding to the pump of the system being in the dispensing position, and the regulator automatically returning to the original shape when the external force is removed, whereby the regulator forms part of said return means, and in that the regulator is resilient along the length of the stem. - a collapsible container for liquid material and - a pump being sealingly connected to the collapsible container for withdrawal of liquid material from the container during collapse thereof, - the pump comprising -- a housing forming a chamber and a dispensing opening, wherein the pressure in the chamber may be varied for pumping liquid from the container to the chamber, and further from the chamber to the dispensing opening, -- and a regulator being fixedly arranged in the chamber for regulating a flow of liquid between the container and the chamber, and between the chamber and the dispensing opening, -- wherein the pump may assume a closed position, in which a volume of liquid is drawn from the container to the chamber by means of a negative pressure created in the chamber, -- and a dispensing position, in which a volume of liquid is drawn from the chamber to the dispensing opening, the pump consisting of plastic materials; -- a housing forming a chamber and a dispensing opening, wherein the pressure in the chamber may be varied for pumping liquid from the container to the chamber, and further from the chamber to the dispensing opening, -- and a regulator being fixedly arranged in the chamber for regulating a flow of liquid between the container and the chamber, and between the chamber and the dispensing opening, -- wherein the pump may assume a closed position, in which a volume of liquid is drawn from the container to the chamber by means of a negative pressure created in the chamber, -- and a dispensing position, in which a volume of liquid is drawn from the chamber to the dispensing opening, the pump consisting of plastic materials; -- return means automatically returning the pump from said dispensing position to said closed position, whereby the return means uses the resiliency of said plastic material for overcoming a negative pressure created in the collapsible container during emptying thereof,