Fourteen infants in China have been hospitalized with kidney stones after drinking a reduced-price powdered milk, Agence France-Presse reported Wednesday.

The babies, who are all under the age of 11 months, are being treated in a hospital located in northwest China’s Gansu province.

“It was rare for babies to get kidney stones, let alone so many babies at the same time,” said Dr. Zhang Wei, who is treating the babies, in a report.

The infants are all from remote farms. They had been fed the same powdered milk, which is known as Sanlu, and is manufactured by a leading Chinese dairy products company.

The Sanlu Group said its product was produced by market pirates illegally using the group’s name and they are investigating the incident.

It is possible other children became sick by the powder but did not seek medical attention because of the high cost of health care.

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