This ancient self-care practice is easy with the original heatless, less-mess, reusable Castor Oil Pack. Designed by a naturopathic doctor, the Liver Pack is made with an inner 100% organic cotton layer that touches the skin, an outer less-mess layer of polypropylene, and stretchy, adjustable straps made from nylon. • No uncomfortable buckles, buttons or itchy velcro, your Castor Oil Pack for Liver is comfortable enough to sleep in and wraps around your body like a nice warm hug.