Despite quotidian occurrence of fever and hyperthermia, cell biological mechanisms underlying their effects remain unclear. Neurological complications of severe (> 40 °C) fever have been associated with increased blood-brain barrier (BBB) permeability due to structural disruption, while little is known about brain physiology of moderate fever. Here, we show that a temperature increase to 38–40 °C induced fluid-phase uptake in cultured cells. Uptake of selective cargoes showed that clathrin-mediated endocytosis and macropinocytosis were upregulated in a translation-dependent manner, consistent with a role for heat shock response. Exocytic recycling was also increased by hyperthermia, suggesting a comprehensive boost of membrane trafficking. Whole-body hyperthermia in vivo triggered fluid-phase uptake in various organs, notably enabling brain accumulation of an intravenously injected antibody that was blocked by dynamin inhibition. Taken together, our findings show that temperature systemically regulates membrane trafficking, reveal dynamin-dependent endocytosis as a cell biological mechanism for temperature control of BBB permeability, and demonstrate a clinical potential of hyperthermia for facilitating brain delivery of biologic drugs.