Dr. Mercola discusses a recent study that shows common moisturizing creams containing mineral oil can increase risk of skin cancer. Mineral oil is a petroleum product and there's nothing natural about it.
http://articles.mercola.com/sites/articles/archive/2011/06/21/is-your-moisturizer-causing-skin-cancer.aspx
http://articles.mercola.com/sites/articles/archive/2011/06/21/is-your-moisturizer-causing-skin-cancer.aspx