A probe has been launched in Gansu province after thousands of students fell ill after taking tainted iodine pills sold to them at grossly inflated prices. Education officials in the province's capital, Lanzhou, sold the tablets at hundreds of times the normal cost to the city's 70,000 schoolchildren. More than 6,300 primary students fell ill and had to be treated. On April 11, some 109 children were taken to hospital after suffering vomiting, abdominal pains, dizziness or nose bleeds. In one school, all 470 pupils who took the iodine pills became sick, according to a report in the Guangming Daily. An investigation found that each tablet cost only 77 fen (72 HK cents) but students were told they had to pay 28 to 30 yuan for the medicine. Provincial leaders are now looking into the scam. Governor Sun Ying and Lanzhou Mayor Zhu Zuoyong ordered a swift recall of all tablets and set up a special investigative committee. The incident occurred despite an urgent alert on April 6 by the Education Ministry over suspect pills following a spate of similar poisonings that aroused the concern of President Jiang Zemin.