Two food poisoning cases in Hunan and Shaanxi provinces over the weekend sent more than 300 people to hospitals for treatment.

Victims of food poisoning receive treatment at the Hangtian Hospital in Changsha, Hunan province. A total of 286 villagers were sent to hospitals for examinations and 91 were diagnosed with food poisoning on Saturday after attending a wedding in Wufeng village, Lianhua town, Yuelu district, Changsha. [Photo/China Daily]

In Changsha, capital of Central China's Hunan province, 286 villagers were sent to hospitals for examinations and 91 were diagnosed with food poisoning on Saturday after attending a wedding, according to Changsha-based Rednet.cn, an Internet portal.

The food poisoning is suspected to be the result of ingesting clenbuterol, a substance used to increase the amount of lean meat in pigs, a nurse with the emergency department at the No 3 Xiangya Hospital of Central South University, in Changsha, told China Daily on the phone on Sunday.

Fifteen of the patients at the hospital were in critical conditions, including children and a pregnant woman, she said.

Other victims, though, were only suffering minor symptoms. Many of them had already left the hospital, the nurse said.

"Officials with the local center for disease control and prevention arrived last night, and I heard them say the mass poisoning might be related to clenbuterol," she said.

A staff member of the hospital's duty room said officials from the district's health and epidemic prevention station went to the hospital on Sunday afternoon and took test samples from the patients.

No results from the tests were available by Sunday evening.