(CNN) -- Kindergartens in three Chinese provinces are accused of giving prescription drugs to children without their parents' knowledge, according to Xinhua, China's state-run news agency.
The drugs were given to prevent the children from getting sick in order to boost attendance, the news agency reported. The schools get paid based on attendance.
The scandal started last week in one kindergarten in the city of Xi'an and has now spread to several in the country, prompting China's education and health ministries to require its local branches to check all kindergartens and primary schools for illegally administered drugs, according to the Global Times newspaper.
Almost 2,000 children who attended the suspected kindergartens are receiving medical attention as some reported side effects from the medication, such as dizziness, stomachaches, leg pains and genital swelling, Xinhua said.
In an article Tuesday, state media called it a "crisis of confidence in kindergarten managers." It said that many parents are fed up with private kindergartens "which are poorly funded, poorly managed and frequently in a bad state of repair." China's preschools have been riddled with what the state media called "a long history of avoidable problems" such as food safety and physical abuse.
Some angry parents of the affected kindergartens rallied in front of the facilities and local government buildings.
Last week, Xinhua reported that a parent accused a kindergarten in Xi'an, in Shaanxi province of administering an antiviral drug to children.
One parent told the Global Times that several kindergarteners had been complaining about stomachaches or night sweats. When their parents took them to the doctors, they found abnormal results in urine and blood tests -- traces of possible damage to the kidney or liver, the parent told Chinese media. The doctors were stumped over the diagnosis.
Local authorities said that the administrators at the Fengyun Lanwan Kindergarten had given children moroxydine ABOB, a medicine which can cause side effects such as sweating, loss of appetite and hypoglycemia since 2008. The prescription drug is used to treat the flu.
"Teachers told my child the pill was good for him but should be kept secret," one parent, identified as Zhang told Xinhua. "They have been taking it for nearly three years."
Another kindergarten in Xi'an, called Hongji Xincheng has also been suspected of following the same practice, Xinhua said. Together, the two kindergartens have 1,455 students.
Little known about drug in question
Dr. Nelson Lee, professor of infectious diseases at the Chinese University of Hong Kong, said not much is known about moroxydine ABOB.
The drug was produced in the 1950s and could have some antiviral effects such as suppressing the flu virus, but there are no reports or clinical trials in English.This means doctors know little about how helpful or harmful it could be.
For kindergartens to administer such a drug with little research or data is something Lee said he has never heard of.
"I think the most effective, suitable way to prevent flu infection is to ask the students to get flu vaccines every year. It's the proven, safest way to prevent flu, rather than taking long-term medication with unknown side effects and efficacy."
Similar incident in Jilin province
Days later, another kindergarten came under scrutiny, this time in the northeastern province of Jilin.
Investigators told Xinhua that a branch of the Fanglin Kindergarten in Jilin City had given some children the same drug -- moroxydine ABOB -- to prevent them from catching colds and infectious diseases. The kindergarten staff were reported to have said they were using the drug to improve attendance.
Three administrators have been arrested, according to Xinhua.
The kindergarten's 375 students are getting checked at hospitals, it reported.
Latest incident in Hubei province
The parents of children who had been attending Xingang Kindergarten in Hubei province, had become suspicious, telling Xinhua that their children developed symptoms such as stomachaches, irregular heartbeats, itching, vomiting and dizziness. Kindergarteners told their parents that they were forced to swallow "white, bitter-tasting pills."
The principal and vice principal of the kindergarten "admitted to having fed pupils an over-the-counter anti-fever drug and vitamins to boost their immunity and improve attendance," reported Xinhua on Tuesday.
The kindergarten, located in Yichang City, was shut and about 200 students are receiving medical check-ups, according to China's state media.
Authorities are looking into where the schools got their supply of prescription medication.