Gag Reflex: Bears, like many animals, have poor gag reflexes. A man recently survived a vicious bear attack by shoving his arm down the bear's throat, causing it to gag and then retreat.
Make Some Noise: Bears can make some intimidating noises, but they aren't a fan of noises they are unfamiliar with. So bring the noise and live to tell about it.
Calm The Charge: While it may be the last thing on your mind, calmly standing your ground when a bear is charging can be the best attack deflector. If you get a bluff attack as a warning, stand, wave your hands, and talk calmly to the bear.