tOral ingestion of a toxic lithium chloride (LiCl) solution yields a conditioned aversion to asafe sodium chloride (NaCl) solution in rats, presumably because of the common qualityof saltiness. By using this generalized bait-shyness paradigm, we examined the relapse ofacquired and subsequently extinguished salty taste aversion. After conditioning by oralingestion of a 0.15 M LiCl solution, extinction was induced by two different experimentalprocedures. In the constant extinction group, rats were repeatedly exposed to 0.15 M NaClsolution. For rats in the graded extinction group, the concentration of NaCl was graduallyincreased from a low level to 0.15 M and an additional interfering sweet taste was graduallyfaded out. Rats in the graded extinction group were more prone to relapse than animalsthat underwent the constant extinction treatment. This difference was manifested in thefollowing three response reoccurrence phenomena: renewal upon return to the acquisitioncontext (Experiments 1A–C), spontaneous recovery after a 23-day interval (Experiment 2),and reacquisition caused by the second LiCl intake (Experiment 3). Theoretical and clinicalimplications of these results are discussed.