Parents take their children for medical treatment at the Children's Hospital of Zhengzhou in Zhengzhou, capital of central China's Henan Province, Sept. 17, 2008. According to the data released by the health bureau of Zhengzhou City, up to 8 a.m. of Sept. 17, 261 cases of kidney stones were diagnosed among 3,244 infants drinking Sanlu's tainted baby milk powder. The chemical melamine was added to the milk as it was believed to have helped to increase protein content.