Question: how long does it take for something to bruise?
Answer: When you first get a bruise, it's kind of reddish as the blood appears under the skin. Within 1 or 2 days, the hemoglobin (an iron-containing substance that carries oxygen) in the blood changes and your bruise turns bluish-purple or even blackish. After 5 to 10 days, the bruise turns greenish or yellowish.