A 17-year-old man was admitted to the paediatric intensive care unit 2 hours following an intentional ingestion of unknown substances. In the first 23 hours of hospitalisation, lactate levels remained elevated at 2-4 mmol/L, during the 24th hour, he developed lactic acidosis with lactate levels increasing from 4 to 16 mmol/L. His neurological status declined, requiring orotracheal intubation. Central and arterial access were obtained, and vasoactive infusions were initiated for haemodynamic support. Due to increasing lactate levels (maximum level >24 mmol/L) and haemodynamic instability, a dialysis line was inserted, and continuous renal replacement therapy (CRRT) was initiated. The lactic acidosis resolved over 10 hours. Serum ibuprofen level subsequently resulted at 841 µg/mL (reference range 10-50). Few reported cases discuss the sequela of large quantity ibuprofen ingestion leading to severe lactic acidosis and multiorgan system failure. Early intervention with CRRT may reverse acidosis, stabilise haemodynamics and halt secondary organ failure.