Ditto to what Trisha stated.
Proactiv is basically all clever and smart advertising and marketing. It contains benzoyl peroxide (2.5%) which helps treat acne. You can purchase any type of products with benzoyl peroxide at the drugstore for much less than the thirty or forty dollars per month Proactiv charges you for their kits.
Personally, for me, I used Proactiv and it worked for the most part, though I still had the occasional breakout once or twice a month. I have mild to moderate acne and used the basic kit (cleanser, toner, moisturizer and mask) for about 6 months and then I switched to another regimen (because it was too expensive and also harsh on my skin) and my acne was about the same as using Proactiv. This was probably because Proactiv was my first skin care regimen and because I did not cleanse my skin prior to using Proactiv, I had a lot of acne. Now that I cleanse my skin and use specific treatments for my acne (mask, salylic acid) my skin is clear for the most part. But then, my friends (two of them) who used Proctiv, did not work for them at all and actually made their acne worse. It's all trial and error. For some it may work, for some it may not.
Oh, lastly, the most important thing about using Proactiv is to use a sunscreen (at least SPF 15) because when using benzoyl peroxide, it makes your skin more prone to sun damage.
