Epinephrine is a hormone which, together with norepinephrine, is produced by the body in response to emotional or physical stress. The results are several general symptoms which together ready the body for "fight-or-flight" reactions. These symptoms include increased respiratory rate, increased blood pressure, pulse rate and cardiac output, increased muscle strength, increased blood supply to major organs (brain, heart, kidneys), decreased blood supply to periphery (skin) and intestines.

Epinephrine is marketed under the trade names Adrenalin, Bronkaid Mist, Primatene Mist and Sus-Phrine to treat several conditions including asthma; high levels of epinephrine have been reported in anxiety disorders, although it is not yet clear whether this is a cause or effect of those disorders (i.e., whether individuals experience a panic attack because of overrelease of epinephrine, or whether a panic attack stimulates overrelease of epinephrine).