CPN-UML Chairman KP Sharma Oli has been admitted to the Maharajgunj-based Tribhuvan University Teaching Hospital (TUTH) on Saturday.
Oli was taken to the District Police Range, Kathmandu after being arrested from his residence in Bhaktapur this morning.
Immediately, police took him to the TUTH for a routine health check-up.
Although preparations were underway to keep him in custody, doctors advised that he be admitted to the hospital for observation, according to a source.
Oli is a patient of kidney transplant.