There have been reports that hyperammonemia and amino acid disturbance can cause loss of consciousness in patients with multiple myelomas and normal liver function. We experienced a case of a 71-years-old female patient with amyloidosis, who had shown disturbance of consciousness. At that time, the serum ammonia level was elevated; serum amino acids disturbance was also noted. In particular, the decrease in branched-chain amino acids and increase in aromatic amino acids results in a low Fisher ratio. The Fisher ratio, the ratio of branched-chain to aromatic amino acids, has been suggested as an important indicator of consciousness disturbance. We report, for the first time in Korea, a case of amyloidosis, with mental disturbance due to serum amino acid disturbance.

Keywords: Amyloidosis, Amino acid disturbance, Hyperammonemia