The article analyzes the effects of the appreciation and depreciation of the Polish zloty against the euro. The author argues that sensitivity to the impact of exogenous shocks is a characteristic feature of small and medium-sized open economies, which also include Poland. According to Karp, exchange rate fluctuations are disturbances that have a strong impact on foreign trade, the price level and the entire economic system. Due to the complexity of the relationships between economic variables, an appropriate analysis must be conducted on a complete macroeconometric model, the author says. Analysis was conducted on a monthly model of the Polish economy (WM-1) that also contained asymmetric equations based on the threshold-error correction model (TECM). In two simulations, symmetric exogenous shocks – persistent for three months and directly causing the Polish zloty to either appreciate or depreciate – were assumed. These impulses set off the exchange rate multiplier effect and consequently the reaction of the whole economic system. The responses of the variables are asymmetric depending on the direction of the impulse, the author says. The simulation analysis shows stronger reactions when the zloty appreciates than when it depreciates. Although the initial impulse directly affects the “nominal” economy, its impact also influences the real economy by affecting production, investment and employment, the author concludes.