AbstractWe studied the effects of methanol, ethanol,iso‐propanol, andn‐propanol on the reaction of hemoglobin with oxygen at various temperatures. The analysis of the results in terms of the Monod‐Wyman‐Changeux model allowed determination of the overall contribution of the alcohols to the standard enthalpy and entropy differences between the T and R states of hemoglobin. A phenomenological approach allowed us to obtain separately the contributions related to the variations of the bulk dielectric constant of the solvent (bulk electrostatic contributions) and the contributions related to other effects (non‐bulk‐electrostatic contributions). The values of non‐bulk‐electrostatic contributions to ΔΔHand ΔΔSsupported the suggestion that these contributions are mainly related to protein‐solvent hyd