When taking a solo weeklong backpack into the smokies a year or so ago I bought a large can of bear spray from an outfit in the NW.
Curiously it has a large safety warning label that reads:
"Warning; do not seek out bears to try this out on. It may not work"
The can was so awkard to carry that it ended up buried in my pack the whole trip. By the time I climbed the first 5+ mile uphill with 50 lbs on my back the last thing on my mind was bears.
There is an excellent text on how to deal with black bears available from Smokey Mountain National Park. Worthwhile read for the eastern U.S. (pepper spray is not mentioned, Park rangers will confiscate any carried in the open.)