Mrs Gandhi, 66, was led limping out of the lower house on Monday evening by her son and colleagues, and then taken by car to the All India Institute of Medical Sciences hospital in New Delhi.
A Congress party official said that Mrs Gandhi had suffered a touch of viral fever and was now fine.
The Italian-born politician, who has led her party to two successive terms governing the world's largest democracy, has played a slightly reduced public role since being treated abroad for an unconfirmed illness in 2011. Despite this, she was named the world's sixth most powerful woman by Forbes magazine last year.
The party is usually very secretive about Mrs Gandhi's health but several media reports said in 2011 that she had been treated for cancer at New York's Sloan-Kettering Cancer Centre.
Mrs Gandhi had been participating in a parliament debate on a scheme to provide cheap food to more than two-thirds of India's poor - one of her personal projects - when she felt unwell.
She and her son Rahul are banking on the nearly £13billion food security programme to boost the Congress Party's prospects ahead of next year's election. The party's campaign is built around the two members of the Nehru-Gandhi dynasty.
The normally strong- looking leader trembled as she read a short speech on the food security bill, one of the world's largest welfare programmes and one Mrs Gandhi has insisted on to ensure India's poor are not left behind in its emergence as a global economic power.