Boudreaux"s Butt Paste Maximum Strength was formulated by a respected pediatrician to provide quick diaper rash relief on first use. With 40% zinc oxide, it"s the strongest formula without a prescritpion. It forms a protective layer around your baby"s skin to help seal out wetness and includes natural ingredients such as Peruvian Balsam to promote healthy skin. Easy to apply, easy to clean and smells wonderful. Dermatologist tested to kick some rash.