Described is a method of treating a skin condition in a subject. The method includes applying topically to the subject an effective amount of an aqueous Astragalus seed extract solution to a skin area in need of reducing or slowing the skin condition. The aqueous Astragalus seed extract solution is prepared by a procedure including the steps of: soaking dried seeds of Astragalus seed in an aqueous solvent to form a suspension； boiling the suspension for at least 30 minutes； and filtering the suspension so as to obtain the Astragalus seed aqueous extract solution, the weight ratio of the dried seeds of Astragalus seed to the extract solution being 1:100 to 75:100.
