Ok, call me extremely stupid (hey I'm 16), but I let my friend spray me with this bear spray... Let me tell you, I never want to do it again. This stuff dropped me, all 6 foot 3 inches of my lean muscle :). I didnt cry like my friend did when he was sprayed, but I didnt want to do anything but get to water. I was out of it for a full 30 minutes. My nose was gushing snot, my eyes were tearing, I couldnt breath right, and I couldn't open my eyes. I cant imagine the pain that a bear would feel if it wasnt near water.
Of course I'm not a bear, but I imagine that a bear (because its nose is more sensitive) would be just as effected as I was.