By means of an automated single‐lever shock‐avoidance procedure, guinea pigs were conditioned to track absolute thresholds to a thermal noise stimulus. Threshold measurements were made under control conditions and 1–2 h following a single intraperitoneal injection of sodium salicylate. A temporary threshold‐shift function was obtained for dose levels from 50 to 250 ms/ks of salicylate. Contrary to expectation, threshold shifts were not produced when salicylate doses below lethal amounts were cumulated over 4 days' time. Failure to demonstrate drug‐induced TTS under chronic‐dose conditions is discussed in terms of blood salicylate levels. Data are presented that suggest that the analgesic property of salicylate can account in part for the hearing‐loss function obtained with avoidance‐conditioning procedures. [Work supported in part by the National Institute of Neurological Diseases and Blindness, U. S. Department of Health, Education, and Welfare.]