Human have blue coloured blood in veins In reality, there is no blue human blood. The misconception is that the oxygenated blood is red and the deoxygenated blood is blue in colour. And thus veins carry blue blood. But the fact is that the veins carrying deoxygenated blood appears blue from the skin surface. Light from outside illuminates veins to appear light through the layers of skin. It is not the colour of blood which is blue. The fact is oxygenated blood is dark red in colour and the deoxygenated appears a little lighter red than the oxygenated blood.