Doctors treating outgoing US Secretary of State Hillary Clinton believe that she will make a full recovery.
However, despite the upbeat assessment Mrs Clinton's illness has renewed concerns about any possible future presidential bid.
Mrs Clinton is being treated for a blood clot in her head, but medical staff believe that blood thinners being used can dissolve the clot.
They also say that she didn't suffer a stroke or neurological damage from the clot that formed after she had a concussion during a fainting spell at her home early last month.
Mrs Clinton (65) was admitted to a New York City hospital at the weekend when the clot was found on a follow-up exam on the concussion, according to her spokesman Phillipe Reines.
Doctors have also revealed that the clot is located in the vein in the space between the brain and the skull behind the right ear.
She will be released once the medication dose for the blood thinners has been established, the doctors said.
In their statement, Dr Lisa Bardack of the Mount Kisco Medical Group and Dr Gigi El-Bayoumi of George Washington University said Mrs Clinton was making excellent progress and was in good spirits.
Mrs Clinton's complication is one of the few types of blood clots in the skull or head that are treated with blood thinners, said Dr Larry Goldstein, a neurologist who is director of Duke University's stroke centre. He is not involved in her care.
The area where Mrs Clinton's clot developed is "a drainage channel, the equivalent of a big vein inside the skull. It's how the blood gets back to the heart," Dr Goldstein said.
Mrs Clinton returned to the US from a trip to Europe, then fell ill with a stomach virus in early December that left her severely dehydrated and forced her to cancel a trip to North Africa and the Middle East. Until then, she had cancelled only two scheduled overseas trips, one to Europe after breaking her elbow in June 2009 and one to Asia after the February 2010 earthquake in Haiti.
Her condition worsened when she fainted, fell and suffered a concussion while at home alone in mid-December as she recovered from the virus. It was announced December 13.
Looking to the future, Clinton supporters have been privately, if not publicly, speculating how her illness might affect a decision about running for president in 2016.
Americans admire Mrs Clinton more than any other woman in the world, according to a Gallup poll released on Monday – the 17th time in 20 years that Mrs Clinton has claimed that title. And a recent ABC News/' Washington Post' poll found that 57pc of Americans would support Mrs Clinton as a candidate for president in 2016, with just 37pc opposed. Websites have already cropped up hawking "Clinton 2016" mugs and tote bags.
After decades in politics, Mrs Clinton has said she plans to spend the next year resting. She has long insisted she had no intention of mounting a second campaign for the White House after running in 2008. But the door is not entirely closed, and she would almost certainly emerge as the Democrat to beat if she decided to run again. Her age – and her health – would probably be a factor under consideration, given that Mrs Clinton would be 69 when sworn in, if she were elected in 2016.