Black bear mothers sometimes bluff-charge but rarely attack people. They usually run away. A recent study by the National Park Service showed that bears sometimes are harder to chase after they have begun eating. Some bears in that study gave low intensity threats when people slowly approached closer than 15 feet, but all bears that were chased retreated. No visitors were attacked.
People are often more timid at night, but bears retreat at night as well as by day.
Capsaicin spray repellent usually persuades black bears to leave when it is sprayed into their eyes. Capsaicin, the active ingredient of cayenne peppers, has long been used by mailmen as a dog repellent. In more than 200 trials, no bear gave any sign of anger after being sprayed, sometimes repeatedly. Most immediately turned and ran, stopping eventually to rub their eyes. The repellent irritates the eyes for several minutes but causes no injury.