If you read through Bowel cleanse forum and Parasite forum, etc, you'll find that in most cases dark circles under the eyes are caused by parasites. You need to look into doing intestinal cleanse, parasite cleanse, liver flush, kidney flush, and changing your diet to more raw (fruits and vegetables).
You'll find load of information on forums here (parasite, ask andreas, ask mh, dr. shulze forum, etc).