Nizoral Shampoo is a medicated shampoo that contains ketoconazole, a potent antifungal agent. This shampoo is specifically formulated to treat and prevent dandruff and seborrheic dermatitis, a condition that causes scaly patches and red skin, primarily on the scalp. The active ingredient, ketoconazole, works by inhibiting the growth of fungi, thereby alleviating itching, flaking, and inflammation associated with these conditions.