The blood found in humans is red. Human blood contains a vast amount of red blood cells. Red blood cells consist of hemoglobin. Hemoglobin is red in color, and it contains high iron protein that helps to transport oxygen.
Blood with high levels of oxygen and hemoglobin appear bright red. Blood that is de-oxygenated comes across as a darker red.
There is a common misconception that human blood is blue. This idea generates from how blood can appear blue under the skin in veins. This blue tone appears because of the way that light penetrates the skin. The light illuminates the veins and makes the blood in the vein look blue to the eye.