Dry coating technique has been widely used in reducing cohesion in fine cohesive pharmaceutical powder particles and hence improving flowability. This paper aims at establishing the concept behind cohesion reduction by dry coating. Theory involving the mechanism of cohesion reduction by dry coating is discussed, together with tabulating the primary working principles and major operating parameters of four widely used dry coating techniques namely Comilling, Fluid Energy Milling, Magnetic Assisted Impact Coating and Mechanofusion. This review summarizes the technique of dry coating and the mechanism of cohesion reduction together with discussion of various studies undertaken to test the efficacy of the various dry coating techniques. (C) 2019 Elsevier B.V. All rights reserved.