The main ingredient in soap is tallow products. For those who don't know what tallow is, here's the definition: Hard fat obtained from parts of the bodies of cattle, sheep, or horses, and used in foodstuffs or to make candles, leather dressing, soap, and lubricants.
Hmmm, sounds kind of disgusting. So basically we wash ourselves in animal fat. Yuk. Who thought of this? Ok, I use soap too, but this does sound pretty nasty.