The severity of His Majesty the King's infection has diminished further, the Royal Household Bureau says.
An announcement released on Wednesday evening was made after the King's blood and phlegm were checked by a team of doctors at Siriraj Hospital.
An X-ray found fluid in the King's lung had reduced and there was no inflammation.
A pulse examination by echocardiography found the functioning of His Majesty's cardiac muscle was satisfactory.