A ten year old female spayed Golden Retriever dog presented for treatment of presumptive aflatoxicosis after several other dogs on the same commercial diet died of acute liver failure; quantitative testing subsequently confirmed toxin levels of aflatoxins (239 ppb). The patient was mildly affected and clinical signs were limited to inappetence, vomiting, polyuria and polydipsia. Multiple mild laboratory abnormalities referable to liver damage and hepatic synthetic failure were observed. A nodular hepatopathy was detected on abdominal ultrasound but the significance of this was unclear. Supportive and hepatoprotective therapy was instituted and the patient recoverd over the course of several weeks. General principles of the pathogenesis, diagnosis, and treatment of aflatoxicosis are discussed.