I like OC spray for dealing with hostile animals (not just dogs...had to use it on an opossum once when I didn't have a gun handy). Often, spraying a "line" b/t you & the animal is enough to turn them away. When it isn't, spraying their muzzle changes their mind.
As a former TYC (TX youth prison) employee, I had been sprayed in training. It was distracting, but I could still function well enough to fight. Some others fell down & couldn't function at all. This experience taught me that, if you use OC on a human, be prepared to follow it with another technique to defend yourself (strikes, kicks, blunt force, etc.)
Proud member of Gun Culture 2.0......