This article originally appeared in MindBodyGreen.

Mascaras are a coveted beauty item for many. In one or two swipes, they can define your eyes, make you look more done-up, or simply top off a look. If you are a regular makeup wearer, you likely have one or two favorites that you keep on going back to—and unless you've been a natural beauty enthusiast for a while, there's a decent chance that your mascara is on the more conventional end of the beauty product spectrum.

Why do we make this assumption? Clean and natural mascaras have been one of the hardest to get right without the use of preservatives like parabens or phthalates, ingredients that often pop up on a few "things to avoid" lists. These help limit the growth of harmful bacteria. Given the nature of mascaras, it is essential that they have effective preservative systems. Here's why: Mascara's formulas contain water, which can serve as a germ breeding ground. If you combine that with the fact that you regularly dip a wand in and out, and therefore are regularly increasing the chance for contamination, it can become ripe for infection-causing bacteria.