We report a case of fatal salt poisoning in a 55-year-old woman who suffered from depression and drank a large quantity of shoyu (Japanese soy sauce). She presented with the highest ever documented serum sodium level of 187 mmol/L. This was associated with symptoms of cerebral damage which developed within hours after drinking the soy sauce. She died as a result of massive pulmonary edema, despite intensive medical treatment. Viewing the results of clinical and postmortem investigations together, her death could clearly be attributed to drinking a large quantity of soy sauce.