Tetramine, a rat poison, caused 39 people to be taken to hospital in northwest China's Shaanxi Province last Monday.

The 39 people, including 11 primary school students, exhibited symptoms of food poisoning after eating a cold noodle dish at a restaurant in Foping County. After forensic tests, tetramine was confirmed to be the cause, according to the county government.

It is yet to know whether the case was deliberate poisoning. Police are still investigating the case.

All the patients are now in a stable condition. The three pupils receiving emergency treatment at the intensive care unit have been transferred to the pediatrics department.