Japanese drug maker Kobayashi Pharmaceutical says two more people have died after taking its health supplements that contain "beni-koji" ingredients. "Beni-koji" is rice fermented with red yeast.

Thursday's announcement brings to four the number of people who died after taking the supplements. More than 100 others have been hospitalized after developing kidney problems.

The company says one of the newly identified two took the supplements around 2021, and the other in early 2022.

Their families reported that they showed possible symptoms of kidney disease.

The company says products manufactured from April through December last year may contain an "unintended substance" that caused the deaths and illnesses. It has launched a detailed investigation.

The city of Osaka on Wednesday issued an administrative order to Kobayashi Pharmaceutical to recall three types of "beni-koji" supplements.