A method is described that makes it possible to measure flushing, particularly in the context of the study of rosacea, and to distinguish normal flushing from pathological flushing. Also described, is the use of said method to study the effect of drug candidates, particularly against rosacea. The method can include: a) subjecting the subject to a flushing inducing stimulus； b) measuring the inflow of blood in the face of the subject during a time period covering the flushing； and c) calculating entropy of the inflow of blood.
