67-year-old Sonia was admitted to the Cardiology unit after she complained of exhaustion and was undergoing check ups, hospital sources said, adding that her condition is stable and there was no cause for concern.
The UPA Chairperson, who has been spearheading the UPA's ambitious legislation, was taken straight to AIIMS from the Lok Sabha when the voting was underway on various amendments to the Food Security Bill moved by the Opposition.
Sources said top doctors of AIIMS including its acting director R C Deka are attending on her.
They said she is undergoing some tests and is under observation.
She had viral fever since last night and doctors examined her at her home, sources said.
Earlier in the day, Sonia led the party in the debate on the landmark bill in the Lok Sabha describing it as a measure to wipe out hunger from the country.