Well, yes, Preparation-H can reduce the dark circles under your eyes. First, you should know that a live yeast cell derivative called Bio Dyne, and Bio Dyne, which is a vascular constrictor, are in all Preparation-H. So that temporarily shrinks dilated blood vessels, and, in turn, may reduce the appearance of dark eye circles as well. Also, Preparation-H is an over-the-counter ointment that has been used to alleviate hemorrhoid pain, itch and swelling. Anyway, you can just try it. Also, to get rid of the dark circles under your eyes, there are also some other ways you can have a try. For example, you can have some Moisturizers containing Vitamin E and K, so that it can lessen the appearance of dark circles. Beside, you can eat some black chocolate which are rich in Lutein and zeaxanthin, which can do a good job to your dark circles and the sight. Also, many kinds of oil, such as the black seed oil are very effective to your dark circles too. anyway, just have a try.