Abstract
Trimethylaminuria (TMAU), also known as fish odor syndrome, is a rare metabolic disorder resulting from a deficiency in the enzyme flavin-containing monooxygenase 3, which is responsible for the detoxification of trimethylamine produced during the metabolism of certain foods. This case report describes a 58-year-old male who presented with a sudden onset of fish-like body odor, diagnosed with secondary TMAU likely triggered by liver cirrhosis and dietary supplements. The report outlines the clinical presentation, diagnostic approach, and management strategies for this rare condition. LEARNING POINTS: Doctors must be aware of the side effects of dietary supplements and actively ask about their use.Trimethylaminuria is a rare metabolic disorder, but doctors should be aware of it.