To obtain an antistain agent capable of effectively inhiviting a harmful action of a contaminant to keratins and to provide a use for the antistain agent.

At least one grain extract is used for topical application as a heavy metal scavenging antistain agent, especially a stain preventing cosmetic. The grain extract used is an aqueous-alcoholic extract of maize. This beauty culture treatment method protects a keratin substance from a stain action, particularly heavy metal action. This method comprises applying a composition containing at least one aqueous, alcoholic or aqueous-alcoholic grain extract in a physiologically acceptable medium to a keratin substance.