I love the Beauty Brains blog - they take a lot of the nonsense used in advertising for a variety of beauty products and explore the truth or falsehood behind it.
The natural/organic/paraben free/etc. issue is one that particularly annoys me. I will confess to having bought into it for a while. Then I started really reading product labels and did a bit of my own research (in more than once place, I might add) and discovered that, for the most part, it's nonsense. I have no problem with people choosing to purchase so-called "natural" products. It's just the claim that they are intrinsically better that gets to me. The fact is, the products often use nearly identical formulations to "non-natural" products, that the terms "natural" and "organic" don't have a real meaning or an official definition by law in the US, and that frequently the quantity of a particular ingredient or group of "natural" ingredients in a product is so small as to be virtually negligible. Even claims about packaging and environmental impact or animal testing can be a bit...weasely. These are also things that are unregulated or only loosely regulated.
"Natural" ingredients can be every bit as dangerous, and sometimes more so, than "artificial" ingredients - people can be every bit as allergic to one as the other. Certain essential oils can increase photosensitivity in skin. As the Beauty Brains article linked to below mentions, a few studies have shown a potential link between tea tree and lavender oils and growth of breast tissue in boys.
Does this mean you shouldn't use them? Good lord, no! It simply means that you should do a bit of digging, not buy into the hype of ANY product, and choose what works for you.
For example, I tend to have a mild to moderate allergic reaction to some artificial fragrance formulations, ranging from a migraine headache to hives. Because of this, I usually often better luck with products labeled "natural" because they frequently seem to use a different fragrance base or formulation, but I also have very good luck with products labeled "sensitive" or "fragrance free". It isn't always the case though and I have to be cautious.
And, of course, things like mercury, arsenic, uranium, ragweed, poison ivy, venom, and poop are all "natural" but I don't think you want them in your personal care products.
More Natural Cosmetic Nonsense | The Beauty Brains