The children suffered from nausea and complained of stomach ache after taking the tablets as part of the state's Weekly Iron Folic Acid Supplementation programme to eradicate anaemia from Haryana.
"The students found suffering from mild side effects will be administered sub normal dose of 60 mg for four weeks to accommodate the absorption of iron," Rakesh Gupta, Mission Director, National Rural Health Mission (Haryana), said.
Most of the children, belonging to various districts including Hissar, Jind, Sonipat, Gurgaon and Faridabad, were discharged after treatment.
Out of nearly 16 lakh children who were administered the tablets in schools in 21 districts, about 900 were found suffering from mild side effects such as nausea and stomach ache, the Mission Director said.
Some 100 more were suffering from general side effects like severe diarrhoea and vomiting, he said.
Gupta advised all those engaged in the WIFS campaign not to administer these tablets to children who are on fast or observing 'Rozas'.
"These tablets should also never be taken with milk or any other dairy product," he said.
Gupta asked people not to panic as the campaign had been launched after extensive discussions among doctors. The programme was also approved by the World Health Organisation and the UNICEF, he said.