Cosmeceuticals are used for nourishing and improving the appearance of the skin and are also documented as effective agents for treating various dermatologic conditions. Cosmeceutical preparations from herbal origin are most popular among consumers because these agents are mostly nontoxic and possess strong antioxidant activity. Because oxidative stress is one of the major mechanisms for skin aging and dermatologic conditions, phytochemicals with proven antioxidant activity, such as silibinin, could be useful for treating many dermatologic conditions as well as skin aging. Silibinin is a flavonolignan compound from Silybum marianum (milk thistle plant) that possesses strong antioxidant activity and also modulates many molecular changes caused by xenobiotics and ultraviolet radiation to protect the skin. This contribution reviews the evidence generated from laboratory studies to support the scientific rationale for the effective use of silibinin in cosmeceutical preparations.