Abstract: The invention relates to a novel process for the isolation of a hepatoprotective agent Silymarin from the seeds of the plant Silybum marianum comprising (i) Precooling the seeds to (−) 20° C. for 24 hours in a deep freezer/cold room. (ii) Powdering the cooled seeds in a hammer mill, fitted with about 40 mesh discharge screen. (iii) Defatting the seeds by extracting with hexane in a soxhlet type extractor to remove the total quantity of fatty oil without using a scrain. (iv) Extracting the defatted seeds with acetonitrile at 20-30° C. to extract silymarin fraction. (v) Concentration of the sensitive silymarin fraction under vacuum in a agitated wiped thin film evaporator (vi) stirring the silymarin such dry powder with cold dichloromethane at 5° C. followed by filtration and drying with a slow purge of nitrogen gas. (vii) Further purification of silymarin by suspending in 5 times its weight of acetonitrile and precipitating by 8-12 times its weight of water at 20° C.