Secretary of State John Kerry choked up on Wednesday while thanking well-wishers for their support after his wife fell ill earlier this week.
Kerry said his wife, Teresa Heinz Kerry, is "doing better" and "improving" in his first public comments about her health scare.
"I'm humbled by the expressions of support and know that, when she is able, she will thank everybody herself."
Heinz Kerry, 74, was flown to Boston on Sunday after becoming ill on Nantucket, an island off the Massachusetts coast where the couple owns a home. She remains in a Boston hospital under observation.
The family was "deeply grateful" that doctors had, so far, ruled out a brain tumor, stroke or heart attack as possible causes of the seizure-like symptoms she experienced, a Kerry spokesman said Tuesday.
The pair married in 1995. Heinz Kerry's first husband was former Sen. John Heinz (R-Pa.), who died in 1991 when his plane collided with a helicopter checking its landing gear.