Dark circles under your eyes might reveal a couple of "dark truths" about your personal health. They usually occur when you're overtired or developing an illness or an allergy. They can also result from losing a lot of weight. But the discolorations--the result of engorged blood vessels around your eyes--are themselves medically harmless. In fact, sometimes they're not even an indication of physical problems. "They may be frightening, but probably the best thing you can do is to stop worrying about them," says Merrill M. Knopf, M.D., an ophthalmologist in Long Beach, California, and an officer of the California Association of Ophthalmology.

Almost everyone gets dark circles under their eyes from time to time. Dark circles under eyes usually are temporary and not a medical concern. The most common factor is heredity, but any irritant that causes chronic tissue swelling (allergy, fluid retention, eyelash infection, rubbing, sun exposure, metabolic imbalance, medications such as birth control pills, etc.) may contribute. In cases of increased melanin deposition, blepharoplasty or fat grafting surgery will neither improve nor aggravate the discoloration.

Causes of Dark Circles
• lack of sleep
• iron or other vitamin deficiencies
• sickness
• hyper pigmentation
• "excessive" visualization (due to medications such as Retin A)
• visible blood vessels due to fast loss, thin, aging skin or hereditary thinness or superficial vessels
• fat loss in general which causes a sunken look

Home Remedies for Dark Circles
Dark Circles can be removed by applying peeled and grated potato overnight at least three times a week.
Avoiding use of bleach or peels to make the dark circles around eyes light.
Apply vitamin K cream. Although studies haven't looked at the use of topical vitamin K for dark circles under the eyes, preliminary studies have found that vitamin K may help with bruising.
A complete step-by-step nutrition guide to improve your diet thus reducing dark circles.

Take a teaspoon of tomato juice, a few drops of lemon juice, a pinch of turmeric powder (if you are not allergic to it) and a little flour, enough to make a paste.

Massaging eyes with almond oil is of great help. Massage at bed time daily, and in two weeks you will see the difference. It is also a good remedy for dark circles.

Mash a cucumber, with the skin still on it, and apply the juice to your face. Leave it on for at least fifteen minutes, and then wash off. Also, make sure you drink enough water, exercise regularly, and get enough sleep.

Apply a paste of lemon juice, tomato puree, orange lentil flour (masoor dal ) and turmeric powder (if you are not allergic to it) on under eye dark circles. Leave it for 15 minutes and wash it off.
Every morning, after washing your face, gently apply mixture of equal parts of tomato and lime juice; wash after half an hour.

Apply plain cool teabags over closed eyes. Don’t use herbal teabags because most aren't as effective.

Yoga can also help you to get rid of dark circles. Do pranayam for atleast 5 minutes everyday.
Almond helps to remove dark circles and is an excellent "skin food". Remove the cream applied around the eye after 10 min. No cream should be left on the skin around the eyes for long periods.