Trimethylaminuria (TMAU), also known as fish odor syndrome, is a rare genetic disorder that causes a buildup of trimethylamine in the body. The body releases this chemical through bodily fluids, resulting in a strong, unpleasant odor that's often described as smelling like rotting fish. The odor can affect breath, sweat, urine, and reproductive fluids. TMAU has no other symptoms, and affected individuals typically appear healthy.
