A total of 15 lakh students in 20 districts were given the 'blue tablet', as the pill is popularly called, in their schools today as the campaign got underway.
The only district left out is that of Jind where the drive is slated for kick-off on July 29, officials said.
A National Rural Health Mission spokesperson said that of those who took the tablet today, only 70 students complained of mild side effects such as stomach ache and nausea.
Those found suffering from mild side effects will be given sub-normal doses for four weeks to assist in Iron absorption, the spokesperson said.