Brazilian President Luiz Inacio Lula da Silva has cancelled his trip to the World Economic Forum in Davos after falling ill with high blood pressure.
President Lula, 64, became ill as he was about to fly from the north-eastern city of Recife to Davos in Switzerland.
He spent the night in hospital and will rest at home for the next few days.
President Lula, who had been due to receive an award in Davos, was "exhausted" after an intense week, a presidential spokesman said.
Central Bank president Henrique Meirelles will travel to Davos to represent Brazil and accept the World Economic Forum's new Global Statesmanship Award on Lula's behalf.
President Lula had spent Wednesday in Recife following a busy agenda.
The president had complained of a sore throat and a pain in his chest during the day and showed signs of high blood pressure as he was about to depart.
His personal doctor, Cleber Ferreira, who advised that he be taken to hospital, said: "I took the president off the plane. He didn't fly on doctors' orders, but right until the last minute he wanted to travel."
Doctors say the president recovered quickly after being taken to hospital but are advising he takes a few days' rest at his home in Sao Bernardo do Campo in Sao Paulo state.
President Lula is in the final year of his second four-year term - but despite high approval ratings has ruled out standing for a second re-election, which is anyway prohibited under the Brazilian constitution.
Following a landslide victory in 2002, he became the first leftist to hold the country's highest office in nearly half a century.
The son of an illiterate peasant family, he had worked as a peanut seller and shoe-shine boy, only learning to read when he was 10 years old, before training as a metal worker and becoming a trade union activist.
He then helped found the Workers Party (PT) in 1980.