TOKYO (AP) _ Emperor Hirohito discharged a considerable amount of blood Sunday and doctors gave the 87-year-old monarch an emergency blood transfusion, palace officials said.

The discharge contained fresh blood, indicating it came from recent internal bleeding, said Kenji Maeda, Imperial Household Agency spokesman. Doctors believe the emperor has been hemorrhaging from the area of his upper intestine.

Hirohito has discharged blood from his bowels intermittently since he became seriously ill Sept. 19. Palace officials described the discharge Sunday and on three previous occasions as ''considerable,'' and had said one a week ago was ''large.''

Following the discharge, the emperor's blood pressure dropped, but not precariously, Maeda said. He was given 1.3 pints of blood in the transfusion.

That brought the total amount of blood the emperor has received since Sept. 19 to 36.7 pints, more than three times the normal amount in his body.

Maeda said Hirohito was resting in the afternoon in his room at the Fukiage Palace with no other major changes in his condition.

In recent days Hirohito has spent much of the time sleeping, according to palace sources. After a brief visit Saturday, his daughter described him as fatigued.

The emperor's temperature declined again Sunday, following a decision by his doctors Friday to resume the use of antibiotics to control a worsening infection around his bile duct. The doctors had stopped the powerful drugs two weeks ago because of concerns about possible side effects.

Palace officials have refused to confirm or deny reports that Hirohito has cancer.