The students of the girls' school in Gokalpur-Kumbhawas village consumed the pills yesterday after which they complained of stomach pain, giddiness and cramps in hands and legs.
They were were admitted to the local health centre this morning.
Bhagwan Das, headmaster of the school, said the students were given iron pills for the third time.
Chief Medical Officer Vijay Singh Yadav said the girls have been treated and were under observation.
There have been a number of cases of school children falling ill during the past two weeks across Haryana after being administered the pills, which are being given to them as part of a campaign to combat anaemia.