I have always used Castor Oil Packs to strengthen my liver and kidneys. The liver can grow itself back if you take the time to do it.
You get cold pressed castor oil, wool flannel, a heating pad and a piece of plastic - I use a garbage bag. There are sites online that will explain it in details.
I put the castor oil into a sealed container with the wool flannel and shake it up. You want the castor oil to be dripping from it slowly. I then put the container into the microwave for about 15 or 20 seconds - just to get it heated up. I then put a couple of towels onto my bed or couch and lay down on them. Then I take the wool flannel and put it on my stomach. If you are trying to heal the liver, put it a little bit more over your liver, if you are trying to heal the kidneys, put it over that area. Then I put the garbage bag onto the flannel and then the heating pad - all the way on high (or as high as you can handle). Leave it on for at least one hour and meditate on what you are trying to achieve. After you are finished, wipe yourself off with a mixture of Baking soda and water to get your skin back to the proper ph.
Do this for 4-5 days on and then leave off for the remaining days.
The is a good book called Edgar Cayce and the Palma Christi. It tells of all the wonderful things that Castor Oil (the Palma Christi) does!