Chinese consumers are urged to stop taking health supplements made by a Japanese pharmaceutical company that is recently mired in allegations over its product's link to kidney diseases and five deaths, said the China Consumers Association.

Media reports have emerged about a week ago saying that three dietary supplements made by Japanese drugmaker Kobayashi Pharmaceutical were suspected of causing kidney failure.

As of Thursday evening, the company reported five related deaths and more than 100 hospitalizations in Japan. The problematic supplements all contain beni koji, or red yeast rice, which is marketed as helping lower cholesterol levels.

The company said on Friday that puberulic acid — a toxic substance generated from blue mold — likely caused the health hazard.

The China Consumers Association said in a statement on Friday that the three products in question are not sold on the Chinese mainland, but shoppers can make purchases through online shopping websites and offline stores overseas, as well as daigou — agents who make purchases overseas and resell them to Chinese customers.

"Please immediately stop taking these products and contact customer service of Kobayashi," it said. "Those who bought these products via cross-border e-commerce platforms can return products and request a refund through those websites."

"Consumers who have already taken these supplements should closely monitor their health condition and information released by Kobayashi. If feeling unwell, please visit the hospital promptly and contact the company's service center to protect your legal rights," it said.

The association also called for making rational purchases of health supplements and staying vigilant against fake and exaggerated advertising.

On Monday, the company said that it has set up a reception center for handling return and refund requests, and customers can reach out through phones or online channels.

Japanese health officials had so far inspected two factories manufacturing these supplements, the national broadcaster NHK reported. Kobayashi Pharmaceutical, founded in 1886, produces a wide range of products from dietary supplements and healthcare products to home cleaning supplies.

It established its first joint venture company on the mainland in 1995. The company said that its best-selling products on the mainland are body warmers, fever cooling sheets, and pain relief roll-ons that are readily available at convenience stores and online shopping sites in China.

Thanks to the rise of e-commerce platforms and shopping agents, as well as the increasing convenience of international tourism, a wider variety of its products have become available to Chinese customers.

The company's flagship shopping platform and retailers on the e-commerce platform Taobao sell healthcare products for lowering blood sugar, improving eye health, and protecting the liver after drinking alcohol.

According to the company's annual report in 2019, sales to Chinese visitors in China accounted for 69 percent of the total. And sales of over-the-counter pharmaceuticals took up 60 percent of the total sales to foreign visitors.

The pharmacy department of the Chinese Academy of Medical Sciences' hematology hospital said in an article released on Monday that whether the toxic substance in the company's products stems from the fermentation process of raw materials or other manufacturing factors remains unknown. It added that domestic medicines containing red yeast rice that are used to help treat patients with high cholesterol levels are safe.

wangxiaoyu@chinadaily.com.cn