A skin whitening composition includes an extract of black cohosh obtained by sequentially exposing the black cohosh to two or more solvents of varying solvent strengths. The root of the black cohosh can be separately used to obtain the extract. The composition can be topically applied to the human skin and can further include one or more cosmetically acceptable ingredients. A method of suppressing melanogenesis includes topically applying to the skin a composition comprising an extract of black cohosh obtained by sequentially exposing the black cohosh to two or more solvents of varying solvent strength.