Abstract: A method for evaluating rheological properties of certain non-Newtonian liquids employs the principle of a multiple forced flow of a single sample of the liquid through an orifice, thus effecting a significant elongation of the sample. The liquid is forced through the orifice by means of a piston. Preferably, the orifice is built into the piston so that the liquid remains stationary during the piston advance. The timing and rate of the sequential strokes of the piston are controlled and the differential pressure across the orifice is measured. A function between the timing of the piston strokes, the stroke rate and the differential pressure can be determined. The function has been found to represent a relatively reliable rheological "signature" of the tested liquid.