Some of you may have noticed a new symbol that is appearing on skin-care, hair-care and makeup products. It is an open jar with a number followed by the letter "M", which stands for month. The symbol is referred to as Period After Opening (PAO), and is a new system devised by the European Union's cosmetics regulatory branch. The symbol is not required for cosmetic products sold in the United States or Canada, but if a cosmetics company wishes to sell its products in countries belonging to the 25 member nations of the European Union, it is a mandatory labeling requirement. The purpose of this symbol is to give consumers an idea of how long the product can be safely used (or used "without causing harm") after it is opened.