Former British prime minister Margaret Thatcher left hospital Saturday after undergoing precautionary tests, her spokesman said.
Baroness Thatcher, 82, spent the night at St Thomas' Hospital in London where she was driven from her home in the capital late Friday after she fell ill while dining with friends.
"She's very comfortable and she had a comfortable night. She's feeling a lot better, much revived," said Mark Worthington, Thatcher's private secretary, outside the hospital.
He said the former leader of the Conservative Party - who was prime minister throughout the 1980s - was dining at the House of Lords, the upper house of parliament, when she started feeling "slightly nauseous and faint".
"Her legs gave way a little bit under her," he said, although he denied she had collapsed.
"We thought it safest to be sure about these things," he said.
Television images showed Thatcher, wearing a deep red dress, walking to her chauffeur-driven car outside the hospital and pausing to wave to photographers, before being driven away.
Britain's first female prime minister, nicknamed "the Iron Lady" for her uncompromising style, appears increasingly rarely in public since doctors banned her from addressing large audiences in 2002 for health reasons.
She has suffered a series of minor strokes which friends say have affected her short-term memory, leading her to occasionally lose track mid-conversation.
Thatcher's daughter, Carol Thatcher, said her mother had been taken to the hospital as a precautionary measure.
"They decided to err on the side of caution," she said. "But it's good news today. She is doing well."
Sporting her trademark bouffant hairstyle and handbag, Thatcher forced through sweeping changes during her premiership between 1979 and 1990, advocating individualism and the breakdown of Britain's class system.
At home, she remains a divisive figure, hailed by the right who say she revived the economy by clamping down on trade unions and crushing a major strike by coal miners protesting against pit closures in 1985.
But the left say her reforms helped to unpick the fabric of society, particularly in traditional manufacturing heartlands such as northern England.
Abroad, she forged a close relationship with US president Ronald Reagan in the Cold War stand-off with the Soviet Union.
Her popularity soared when she sent troops to the Falklands in 1982 after Argentina's invasion of the far-away islands in the South Atlantic Ocean. Britain secured victory in two months.
Thatcher narrowly escaped injury from a bomb planted by the Irish Republican Army (IRA) at her hotel during the Conservatives' annual conference in Brighton, southern England, in 1984. Four people were killed.
She was eventually toppled from within her own party when her resistance to closer European ties triggered a revolt which led to John Major taking over in 1990.
She spent longer in Downing Street than any other British prime minister in the 20th century and remains an icon for the right wing of the Conservatives, now Britain's main opposition party.
After leaving the top job, Thatcher was appointed to the House of Lords as Baroness Thatcher of Kesteven. She wrote best-selling memoirs and gave lucrative lecture tours.
Her husband of 52 years, businessman Denis Thatcher, died in 2003. (AFP)
Former British PM Thatcher leaves hospital