Type I autoimmune hepatitis usually has an indolent presentation and course, and is classically thought of as a disease of young women, but can in fact occur across all age ranges. Although its etiology remains unclear, it is hypothesized that an environmental antigen may trigger the disease in a genetically susceptible individual. Here, we report the unusual case of a woman in her seventh decade who presented with acute liver failure as her initial manifestation of autoimmune hepatitis, and who had been a long-time ingestor of hand-picked, wild mushrooms.