Owing to the problems associated with clay swelling, the implementation of surfactant flooding, a well-advised chemical enhanced oil recovery (EOR) technique for sandstone reservoirs, should be implemented with more sensitivity. This paper conducts for the first time a comprehensive study for assessing the performance of a novel natural surfactant, Mulberry leaf extract, on oil recovery from montmorillonite (MMT, as swelling clay) rich reservoirs. From batch equilibrium tests, it was found that MMT appears to have a high potential for attracting the surfactant. In addition, Freunlich isotherm suited the equilibrium adsorption data very well. Based on linear swelling and plugging tests, the adsorption of surfactant restrained the hydration and swelling potential of MMT effectively, thereby no concern about surfactant loss. Micromodel observations exhibited that the proposed surfactant improved the sweep efficiency of water flooding about 11.73%. It was concluded that interfacial tension reduction and swelling inhibitive feature are responsible for excellent performance of the proposed surfactant. (c) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.