Mediums of exchange, such as money, vouchers, and digital currency, facilitate the exchange of goods and pervade modern economic transactions. By and large, the economics literature assumes that the involvement of mediums does not influence economic and exchange decisions. The present research examines the influence of nominal medium involvement on prosocial resource allocation. In seven pre-registered experiments, the authors find that mediums inhibit prosocial giving: in resource-allocation decisions, prosocial giving is more likely when valuable resources are presented as consumable goods than when presented as mediums that exclusively represent consumable goods, holding fungibility and economic value constant. This medium-friction effect occurs because mediums, compared with the consumable goods they represent, are less likely to trigger imagery processing and associative affective and behavioral responses, such as “warm-glow” giving. These findings challenge assumptions about medium neutrality and shed new light on automatic responses as underexplored drivers of prosocial decisions.