Following lesions in the lateral hypothalamic area, animals failed to drink water for several postoperative days. This dysfunction was attenuated or prevented completely in rats that were subjected preoperatively to a restricted daily watering regimen. Postoperative drinking was vigorous and was not feeding associated. Reactivity to sensory stimuli was enhanced both pre- and postoperatively, particularly to stimuli associated with water. Larger lesions produced longer periods of adipsia which were resistant to the preoperative regimen. Restricted watering may exert its protective action by means of several central and peripheral mechanisms, but a behavioral/physiological conditioning hypothesis is emphasized.