Beauty treatments often contain water - creams, lotions, milks - and, therefore, need to be protected from air, bacteria and pollution. There are loads of synthetic preservatives that prevent cosmetics from going off, but not everyone's a fan. Organic skin products don't contain synthetic preservatives and must use natural equivalents. This means they may contain perfumed substances or essential oils that can cause allergic flare-ups. A small dose of alcohol is a chemical-free alternative, particularly if it's of plant origin - fermented wheat, for example. A skin-friendly option, seeing as repeated or long-term exposure to chemical preservatives can pose a risk to our health. On the downside, lots of manufacturers try to convince us that their products are completely 'natural' through clever labels that evoke the natural world. Deceptive product names and canny advertising are also well-known marketing tools. Words like 'green' and 'pure' are thrown about, but more and more of us are learning to weed out the culprits.