Two experiments were run to evaluate the role of acetaldehyde and the area postrema in the acquisition of an ethanol-induced conditioned taste aversion. An ethanol-induced taste aversion was observed in male Sprague-Dawley rats with a dose of 4 g/kg. PO, but not after doses of 1 or 2 g/kg. Pretreatment with 4-methylpyrazole (8 mg/kg, IP), which itself did not induce an aversion as compared to pyrazole (68 mg/kg, IP) that did, and/or prior application of lesions of the area postrema had no influence on the development of an ethanol-induced taste aversion. The results indicate that ethanol-induced taste aversion learning does not result from the metabolism of ethanol to acetaldehyde and does not, like other toxins, involve the mediation of the area postrema.