The sick, mostly children below the age of 14, were being treated at two hospitals in Pingliang city, Xinhua quoted a press release as saying.
It said one of the patients was in critical condition while the rest were stable.
An initial investigation showed that all the patients were poisoned by nitrite after drinking bulk milk provided by two local dairy farms.
The two farms were sealed off and their managers were being questioned.
Published 08 April 2011, 04:27 IST