Oxalate kidney injury can manifest as oxalate nephropathy or nephrolithiasis and present as acute kidney injury or even as end-stage renal disease. There are several known causes for acute oxalate nephropathy; however, the combination of exocrine pancreatic insufficiency with overconsumption of vitamin C has not been described before. In this case, a man in his early 80s presented with anorexia and extreme fatigue for 1 week. He had a history of myalgic encephalomyelitis, also known as chronic fatigue syndrome, for which he took several supplements, including high doses of vitamin C. Furthermore, several years ago, he was diagnosed elsewhere with exocrine pancreatic insufficiency. On admission, acute kidney injury was diagnosed. The kidney biopsy showed oxalate nephropathy as the cause. We diagnosed acute oxalate nephropathy due to high vitamin C doses and exocrine pancreatic insufficiency. Within 14 days, his kidney function got worse and he required renal replacement therapy.