Here's an interesting discovery, brought to you by the Daily Mail. French scientist Philippe Walter and his team at CNRS tested several samples of eye makeup from the Louvre's collection and confirmed its medicinal properties. You wouldn't think a lead-based eye liner would be safe, let alone beneficial, but apparently at low doses the lead salts produced a "molecule-nitric oxide" which boosts the immune system. Neat!
(image from eye-makeup-guide.com)