The only way to treat that problem is to know the cause. Dark circles could be from fatigue and lack of sleep. They can also indicate liver disease, or iron deficiency, or they could be from an allergy, or it could just be a sign of getting old. If you are concerned about them, please don't just rub on some Fair and Lovely to try to bleach the problem away - see a GP to get a diagnosis about the cause. The doctor can then suggest what will be the best way to treat the cause of the problem, instead of just giving you some stupid cream to make things look okay.