His Majesty no longer has a fever and the King’s heartbeat and blood pressure are normal, the Royal Household Bureau said on Wednesday.
The bureau said in its latest statement that the King has had no fever since Tuesday, and his pulse and blood pressure were normal.
His Majesty's respiration and blood-oxygen levels have also returned to normal, while X-rays found improvements in lung inflammation, the statement said.
The King was able to eat and doctors continued to give him parenteral nutrition and oxygen, it added.
His Majesty has been receiving treatment at Siriraj since returning to the hospital from Klai Kangwon Palace in Hua Hin district, Prachuap Khiri Khan province, on May 31.
People and monks across Chachoengsao on Wednesday prayed for his Majesty's quick recovery from illness.
Religious activities were held at all main temples in all 11 districts in the province, with the main ceremony at Wat Sothonwararam in Muang district.
The prayer sessions followed a comment by Her Royal Highness Princess Chulabhorn on Monday.
The princess told doctors of the Princess Mother's Medical Volunteers during a visit to their mobile unit in Phanom Sarakham district that she would like all volunteer doctors and the people to pray for the King's recovery.