US attorney general Michael Mukasey has left hospital to go back to work after collapsing on Thursday night while giving a speech on national security, BBC reported.
Mr Mukasey, 67, had started shaking and slurring before he collapsed and lost consciousness behind the podium at a hotel in Washington.
Mr Mukasey said on Friday all the tests had come back with good results and that he was feeling "excellent".
The former federal judge became the top US law enforcement official a year ago.
Mr Mukasey's aides said the incident was probably just a fainting spell and that there was no sign of a stroke or heart problem.
The attorney general sent an e-mail to Justice Department employees on Friday saying he was feeling fine.
Shortly after midday (1700GMT), he left George Washington University Hospital in a van with his wife Susan for the short ride back to the department.
Mr Mukasey spoke to President George W Bush by telephone on Friday and White House spokeswoman Dana Perino said the attorney general "sounded well".
He was giving an address to the Federalist Society for Law and Public Policy at the time he collapsed.
He was looked after by members of his own security detail until an ambulance arrived to take him to hospital.
Mr Mukasey took over from his predecessor, the scandal-hit Alberto Gonzales, late last year.