It's called the Women's Wonder Bar and it is supposed to cure PMS. It is flavored slightly with rose and contains soy and "chaste tree berry." On the wrapper, it says "Take sweet revenge on PMS, menopause & everyday cravings with this delicious Swiss chocolate." The chocolate bar, which is from a line of products called Health by Chocolate, takes the marketing approach that overtly says you should eat a lot of chocolate. For example, their FAQ says "Q: What happens if I go on a health by chocolate binge and eat more than one bar? A: You'll be in a very good mood."
Other products include an Instant Bliss Beauty Bar, which contains oils that are supposed to be good for the skin, the Instant Bliss Beauty Drink (essentially the same as the bar, but liquid), and the Beautiful Bones Bar, which is orange chocolate with calcium and vitamin D.
The calcium bar aside, since I have seen many other similar products, I have little doubt that these bars will not "work" in that they won't cure PMS or make your skin perfect. They were all designed with the supervision of an holistic doctor and, if things like soy were enough to prevent PMS, then there would be a lot of women who don't get cramps, etc. I'm not the only doubter, either.
I do think that many people get a moos boost from eating chocolate, though, and as long as it makes you feel good, it's hard to argue with indulging in a piece or two. Just know that you're eating it because it's chocolate, and not for any other reason.