Stocks extended losses on Thursday, and the Dow slid 1 percent, as investors fretted about the implications of the U.S. Federal Reserve's action to flood the financial system with cash.

The Dow's top drags included health-care stocks and banks as financials lost ground following their recent run-up.

The Fed's move to pump another $1 trillion into the U.S. economy, including buying Treasury bonds for the first time in four decades, sparked a slide in the dollar, which in turn triggered a jump in oil prices and other commodities.

U.S. front-month crude shot up 6.5 percent, or $3.11, to $51.25 a barrel.

The Dow Jones industrial average <.DJI> lost 84.51 points, or 1.13 percent, to 7,402.07. The Standard & Poor's 500 Index <.SPX> fell 7.72 points, or 0.97 percent, to 786.63. The Nasdaq Composite Index <.IXIC> declined 8.40 points, or 0.56 percent, to 1,482.82.

(Reporting by Ellis Mnyandu; Editing by Jan Paschal)