Hillary Clinton is “recovering well” from pneumonia and remains “fit to serve as president of the United States”, her doctor said in a letter released by her campaign.
The health details made public by the Democratic presidential nominee included a description of the pneumonia diagnosis Mrs Clinton received last week.
Her illness became public after she left Sunday’s 9/11 memorial service early and was seen on video staggering while getting into a van.
“She is recovering well with antibiotics and rest,” said her doctor, Lisa Bardack, in a letter released by her campaign.
"She continues to remain healthy and fit to serve as president of the United States. "
Mrs Clinton has spent the past three days out of the public eye, recuperating at her suburban New York home. She will return to the campaign trail on Thursday.
“She’s feeling great and I think she’ll be back out there tomorrow,” former president Bill Clinton said on Wednesday, when he stepped in for his wife at a campaign event in Las Vegas.
“It’s a crazy time we live in, you know, when people think there’s something unusual about getting the flu.”
The memorial service episode fuelled long-simmering conservative conspiracy theories about Mrs Clinton’s health.
It also provided a fresh line of attack for rival Donald Trump, who has frequently questioned whether she has the stamina to serve as commander in chief.
At a Wednesday evening rally in Canton, Ohio, Mr Trump noted the room filled with 5,000 people was hot.
“You think Hillary would be able to stand up here for an hour and do this?” he asked. “I don’t think so.”
He later added: “We want her better, we want her back on the trail.”
The Republican nominee, meanwhile, handed over a one-page summary of a recent physical examination to the celebrity doctor Mehmet Oz while taping an episode of Oz’s talk show.
Heckled
But voters will have to wait another day for details as the show does not air until Thursday.
Mr Trump was earlier heckled when he attacked Mrs Clinton during what was supposed to be a speech on helping where the government had failed the people of Flint, Michigan.
“Mr Trump, I invited you here to thank us for what we’ve done in Flint, not give a political speech,” said the Rev Faith Green Timmons, the pastor of the Bethel United Methodist Church.
The Republican nominee said he would go back to talking about the water crisis that has hit Flint’s citizens.
But the interruption seemed to embolden those in the sparse crowd.
One woman shouted that Mr Trump had used discriminatory housing practices in his buildings, causing the celebrity businessman to respond: “Never, you’re wrong. Never would.”
Mr Trump abruptly ended his speech, which had lasted six minutes. More heckling followed him out.
Mr Trump also came under fire in a trove of leaked emails sent by former secretary of state Colin Powell.
He called the tycoon “a national disgrace” and suggests his own Republican Party is “crashing and burning”.
The emails were sent between March 2015 and last month by the respected retired Army general who was secretary of state under former president George W Bush.
Mr Powell (79) has said he does not deny the emails’ authenticity.
In the emails, he said he stayed relatively quiet during the rise of Mr Trump: “To go on and call him an idiot just emboldens him.”
To a former aide he writes: “No need to debate it with you now, but Trump is a national disgrace and an international pariah.”
Obama
He also criticised Mr Trump for backing the false claim that president Barack Obama was not born in the United States.
“All his lies and nonsense just pile up,” Mr Powell wrote. “I just go back to the unforgivable one. Trying to destroy the president elected by the American people with his fictitious investigation into this source of birth. Absolutely disgraceful.”
Mr Trump hit back in a Twitter post late on Wednesday, saying: "I was never a fan of Colin Powell after his weak understanding of weapons of mass destruction in Iraq = disaster. We can do much better!"
Meanwhile Mr Trump’s wife Melania released a letter on Wednesday from an immigration lawyer that provided more detail on what she said was her legal pathway to US citizenship.
The two-page letter from Michael J Wildes, posted on Mrs Trump’s Twitter account, marks the first time that she has publicly identified the type of visas she held and gave specifics about her entry into the US.
PA