Disclosed is a method for selectively removing virus and/or virus DNA from an aqueous solution comprising a target protein, said method comprising: a) adding acetone to the solution at a concentration which selectively precipitates the virus and/or virus DNA, b) performing a separation step to separate precipitated material from the solution comprising the target protein, c) adding to the solution an additional amount of acetone to reach a final concentration which precipitates the target protein, and d) collecting the precipitated target protein from the solution； wherein the concentration of acetone in step a) is 12-40% (v/v).
