Used acute esophageal-fistula albino Wistar rats with stomach catheters to separate the roles of taste and feedback in sodium hunger. Of 294 fistulated rats put into the test cages, 171 provided usable data. The effects of sodium deficiency (D; dialysis with glucose) vs. nondeficiency (D; dialysis with saline) were observed on drinking of water and of saline (4 real-drinking, nonoperated groups). These same factors plus the effects of intragastric injection of water or saline (8 groups) were investigated in sham drinkers. Results indicate that (a) the initial positive response to saline by deficient Ss did not appear in acute sham drinkers whether sodium feedback occurred or not; (b) in the later portions of the 12-hr test, a need-related response appeared that seemed to be based on feedback. (PsycINFO Database Record (c) 2006 APA, all rights reserved)