INTRODUCTION: As recently as 2014, Rosuvastatin was the most prescribed brand name drug in the US, with 22.3 million prescriptions filled and $5.8 billion in sales. Its use is associated with mild, asymptomatic, and usually transient, serum aminotransferase elevations, occurring in 1-3% of patients. However, levels above 3 times the ULN occur no more frequently among rosuvastatin-treated [0.2%] as placebo-treated [0.3%] recipients. Rarely, patients can present with clinically apparent acute liver injury, occurring in 1/10,000 patients. CASE DESCRIPTION/METHODS: A 47 y/o Peruvian man was told by his PCP that he had high cholesterol, and he was started on rosuvastatin 5 mg daily. At the time, his LFTs showed AST 17 and ALT 19. However, labs performed a month later showed AST 1282, ALT 2245, ALP 295, total bilirubin (TB) 7.1 (direct 5.5). He was advised to visit his local ER. He was admitted, the rosuvastatin was stopped, he received mainly supportive care, his LFTs continued to rise, and he underwent a liver biopsy. He was then transferred to a tertiary care hospital. His labs upon arrival showed AST 1400, ALT 2253, ALP 277, TB 9.9, and INR 1.1. He was admitted for acute liver failure due to drug-induced liver injury from rosuvastatin. Despite IV NAC therapy for five days and initiation of Ursodiol, his LFTs showed no recovery. His liver biopsy showed acute severe hepatitis with a mixed inflammatory infiltrate with many plasma cells. There was interface activity and bile duct damage. The histopathology was consistent with an immune-mediated drug reaction. He was approved to be listed for liver transplantation due to a high MELD score of 21. Before discharge, his labs improved to AST 942, ALT 1312, and ALP 167, but the TB rose to 17.2. He remained hemodynamically stable with no mental status changes during the hospital course. Afterward, repeated labs showed improvement in the LFTs, except for increasing hyperbilirubinemia. He was re-admitted and given a trial course of IV methylprednisolone after which the TB proceeded to decrease. Ultimately, his liver enzymes improved, he remained asymptomatic, and he was removed from the liver transplantation waitlist. DISCUSSION: The acute liver failure attributed to rosuvastatin is often accompanied by autoimmune features and may be caused by immune mechanisms. Corticosteroids have been used when recovery does not occur promptly. If used, the dose and duration of treatment should be kept to a minimum, and careful follow up after discontinuation is essential.