It's a non-lethal chemical agent that can be sprayed into an attacker's face or into the air.
But it's also sometimes used as a weapon on innocent people.
Take action:
Make sure you know how to treat a pepper spray victim: milk, a paste of baking soda and honey are said to help remove traces of pepper spray from the skin and face.
But actually, there are only two things that can reverse the effects of pepper spray and these are time and fresh air.
Some relief can be provided by flushing the eyes with copious amounts of water.
Constant blinking also helps, as tears can help to wash out the irritant.
Image: Wikimedia, Willi Wallroth