Contains 4% hydroquinone to reduce hyperpigmentation and other key ingredients, such as Vitamin C, to maintain the appearance of aging skin. Prescription required. Contact your healthcare provider to purchase, or find a nearby physician who offers this product. IMPORTANT SAFETY INFORMATION Obagi-C Rx C-Clarifying Serum (Normal to Oily & Normal to Dry) and C-Therapy Night Cream contains 4% hydroquinone CONTRAINDICATIONS: People with prior history of sensitivity or allergic reaction to this product or any of its ingredients should not use it. The safety of topical hydroquinone use during pregnancy or in children (12 years and under) has not been established.