Commercial soaps are supposed to help keep us clean but they often contain numerous chemical components that can be potentially harmful to the body. I recall watching a news broadcast on TV where a chemical analysis was done on a family's blood and there were chemicals in the blood which came from soaps and shampoos. Of course there was the usual disclaimer that there have not been any longer term studies that show that trace amounts of these chemicals are harmful to the body.
Also, many soap strip the skin of its natural oils which it needs. That's one reason why many people have skin that is so dry after they shower. So that's why I recommend mild soap (which most often are used for babies) even for adults.
Anyway, here are some links to some companies that sell soap that is mild, 100% natural, and have as few ingredients as possible:
http://www.blissfulbath.com/view.php?c= ... issfulbaby
http://www.drbronner.com/drb_sai_liquids.html