Why are bruises funny colours?

Professor Hallux investigates!

Bruises can go through all the colours in the rainbow before they heal…

They tend to start red before turning blue… then green, then yellow! Where are all these colours coming from?

Well, at the moment of impact, tiny blood vessels near to the surface of your skin will be broken and the blood in the surrounding tissue will make the area appear red.

Blood’s red colour is caused by oxygen. Over time, that leaking blood will lose its oxygen and so will become purple in colour and then bluey black…

Your body will absorb the blood over time and the blood vessels will heal but any remaining old blood will begin to look green and then yellow as it breaks down.

Don’t worry – one day it won’t be there at all!

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Our bodies are remarkably good at fixing themselves so don’t worry about the colourful nature of bruises.

Some people might say you should put toothpaste on a bruise to make it heal quicker. It’s usually best just to leave it alone though!

You can hear Hallux’s More Physiology Fix-Up weekdays from 6pm on Fun Kids!

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Professor Hallux’s More Physiology Fix-Up, with support from The Physiological Society!

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