Threat changes cognition to facilitate adaptive coping. However, when threat becomes overwhelming, this may be deleterious for mental health especially in vulnerable individuals. Flexible decision-making was probed with a reward reversal task to investigate, how well healthy participants (N=34) can adapt to changes in reward contingency when they expect adverse events (i.e. electric shocks). Relative to a safe control condition, threat-of-shock significantly impaired reward reversal learning. Moreover, enhanced self-reported threat ratings and elevated skin conductance levels support the successful induction of stressfull and aversive apprehensions. Findings are in line with existing literature showing stress-induced inhibition of goal-directed behavior, at advantage of a reflexive (habitual) response style. Notably, reversal learning was rapidly restored with the omission of threat through several cycles of threat and safety contexts within one experimental session. These results extend the current literature and illuminate the immediate consequence of a sustained threatening stressor (and its removal) on decision-making. Better knowledge of the immediate effects of anticipatory anxiety on behavior can improve understanding of psychopathology and may be informative for the development of effective therapy of anxiety and emotion dysregulation.