The concept of someone being �green with envy' is nearly 3000 years old. Certainly, it was used by the Greek poetess, Sappho, in the 7th century BC to describe somebody suffering from unrequited love...in other words, envious of the person who was loved. This was based on the idea that such a bitter emotion caused green bile to flow into the blood. It was used by many other writers down the ages, including Shakespeare who has Iago saying: "...jealousy; it is the green-ey'd monster..." in �Othello'.