The White House said the 3 a.m. trip to George Washington University Hospital was in response to fluid retention as a complication of a drug Cheney, 64, had taken to treat chronic ailments in one of his feet. Last week, Cheney was seen using a cane and the White House said he had a ''pre-existing condition'' in his foot, but the problem was not described with any precision.

President Bush, asked about the vice president, said: ''He's doing fine, I talked to him this morning. His health is good.''

But as is often the case with Cheney, details about what led to his health problem and the exact treatment he received were scarce. Cheney's office said he had been using an anti-inflammatory drug that caused a buildup of fluid in his lungs, leading to the shortness of breath. He began taking a diuretic drug to remove the fluid, his office said. The White House declined to identify the drug that doctors prescribed.