Up to before some 80 years, doctors wore white overalls in operating rooms. This led to assail the psychology of patients, as the stains from the blood appeared to be more on the white surface and seemed more terrifying. Then they made inquiries and found that blood on green blouse becomes less frightening shade and looks more stain brown or sweat. Since then, all the surgeons wear green clothing. Today we see very often and light blue color clothing (skirts) which are of special waterproof material and is disposable.