Thai King Bhumibol Adulyadej, the world's longest-reigning monarch, has been treated with antibiotic medicines and put on a saline drip at Bangkok's Siriraj Hospital, the Royal Household Bureau said Sunday, Reuters reported.
The bureau said in a statement that the revered 81-year-old monarch was admitted to the hospital late Saturday after he developed a fever and showed symptoms of fatigue which reduced his appetite for food.
Prime Minister Abhisit Vejjajiva told reporters earlier on Sunday that the king went to the hospital on doctors' advice for a medical check-up, the second visit in four days.
"There is no problem with His Majesty's conditions. From my chats with doctors, there is nothing to be concerned about," Abhisit said after signing a visitors' log book at the hospital.
The Royal Household Bureau did not make a public announcement on the king's previous check-up Wednesday.
Earlier in March the monarch also spent a day in hospital for a check-up. The bureau released no details of the results, saying it was a private visit.
Last month, the monarch called for unity in deeply divided Thailand in a rare comment on a four-year political crisis marked by violent rallies, assassination attempts, dissolution of political parties and the seizure of Bangkok's main airports.