President George W Bush had five polyps discovered and removed during a routine colon cancer test this morning, the White House said.
They were small and "none appeared worrisome," White House spokesman Scott Stanzel told reporters after the colonoscopy, performed at the presidential retreat in Camp David, Maryland. Further tests will be conducted on the polyps, he said.
At 7.16am (12.16pm Irish time) Bush, 61, invoked Section 3 of the 25th Amendment to the US Constitution to voluntarily transfer his powers of the presidency to Vice President Dick Cheney while he was unable to discharge his duties during the procedure.
He reclaimed his powers at 9.21pm, the White House said. Mr Cheney was at his Maryland home on the Chesapeake Bay, according to the White House.
The amendment has only been invoked twice before in US history, once by Bush in 2002 for the same procedure for just over two hours and once by then-President Ronald Reagan in July 1985 when he had colon cancer surgery.
Bush's colonoscopy in 2002 revealed no medical problems, but he had benign polyps removed from his colon before becoming president, two in July 1998 and two in December 1999.