Just like you prime a wall before you paint it, you can prime your face before you apply foundation. Primers work much like a moisturizer under your foundation does: they ease the application of foundation and are meant to create a barrier between foundation and skin. They’ll even out skin tone, help your makeup stay on longer and absorb oil with salicylic acid.
The primer goes beyond what normal primers do because of beneficial ingredients. Fragrance-free. Lightweight, silky texture smooths skin and refines enlarged pores.
Rather than just being a mix of silicone and fragrance, this combines a dry-finish silicone polymer with emollients, film-forming agents, and copious antioxidants to help smooth skin, temporarily fill in superficial lines, and create an even canvas for foundation.
This formula goes above and beyond most primers. It offers a plentiful range of antioxidants, it’s fragrance free, and is great for oily skin types.
When applied to skin, the green tint becomes a pale flesh tone that provides a bit of coverage. If you have superficial, minor redness, you’ll notice it is less apparent, but that would be true for any tinted moisturizer, too. Anyone with lingering or persistent redness (such as occurs with rosacea) will want to pair this with a foundation that supplies at least medium coverage. One more thing: The finish of this product is matte. It can lend a flat appearance to skin that someone not bothered with oiliness may not like.
Source: Beautypedia.com, beauty.about.com