As you heal, an iron-rich substance in your blood -- called hemoglobin -- breaks down into other compounds. This process makes your bruise change colors:
• It’s usually red right after the injury.
• Within a day or two, it turns purplish or black and blue.
• In 5 to 10 days, it may be green or yellow.
• In 10 to 14 days, it’s yellowy-brown or light brown.
It should fade away totally in about 2 weeks.