This chapter provides information on two experiments that study drinking in the rat induced by intrahypothalamic injections of carbachol solution, determine whether it is affected by altering the palatability and osmotic properties of the proffered drinking fluids. In the first experiment, the palatability and osmotic properties of the drinking fluids were varied by presenting different concentrations of NaCl solution in one-and two-bottle drinking tests. Fluid intakes were similar in this regard to the well-known preference-aversion curves for NaCl solutions produced by rats made thirsty by water deprivation. In the second experiment, body fluid and tissue analyses revealed that there were no changes in plasma volume or osmolarityassociated with the carbachol injections. The fact that drinking induced by carbachol injection can be modified by the palatability of the proffered fluids despite a strong motivation to drink.