Heinz Kerry, 74, an heiress to the Heinz ketchup fortune, was taken from her Nantucket Island, Mass., home Sunday to Nantucket Cottage Hospital Sunday, and was transferred to Massachusetts General Hospital in Boston later in the day, NBC News reported.
No details of her illness have been released, but Sunday CNN quoted a family source who said her illness was "consistent with some sort of seizure."
John Kerry spokesman Glen Johnson said Monday she is undergoing further evaluation, and her husband and other family members are present.
Heinz Kerry, a breast cancer survivor, is the mother of three adult sons from her marriage to Pennsylvania Sen. John Heinz, who died in a plane crash in 1991. She married John Kerry in 1995.
"The family is grateful for the outpouring of support it has received and aware of the interest in her condition, but they ask for privacy at this time," Johnson said in a statement.