Using a raw onion for bruises is an old and traditional remedy.
Onions are great for treating bruises because they have both analgesic (pain relieving) and anti-inflammatory properties.
There’s two popular ways to use onions for bruises. One is simple and very straightforward. The other one requires a bit more effort — but appears to be much more effective.
Whichever method you choose, it’s important not to place the raw onion over any open wounds or cuts (only the bruise, okay?).
The Lazy Method: Slice a raw onion and place it over the bruise. Leave this for 15-20 minutes.
The Enterprising Method: Dice a raw onion. Put one half in a bowl and add 2-3 tablespoons of plain salt. Mix this up well. You’ll need some kind of cloth, towel or bandage. (Do this part in the bathroom since it will get messy. ) Apply the onion mixture over the bruise and wrap the makeshift bandage over to hold it in place.
Tie it firmly so that the onion mix doesn’t fall out. Leave this on overnight. You’ll find the next day that the bruise (along with the pain and swelling) will have gone down significantly.