Blood gets its color from hemoglobin, the protein in your red blood cells that carries oxygen throughout ... has been linked to certain medications. Blue blood isn’t just for royalty.

Blue fingernails may be due to a low level or lack of oxygen circulating in your red blood cells. Other causes include chronic conditions and cold temperatures. Having a blue tint to your ...

While this may sound unusual, animals with blue blood do exist. While most vertebrates, including humans, have red blood cells due to hemoglobin, some animals possess blue blood cells, thanks to ...

After the black-and-blue phase, the bruise begins to fade. It turns green or yellow from the breakdown of hemoglobin, which carries oxygen in your red blood cells. A few days later, it turns ...