Exiled Tibetan spiritual leader the Dalai Lama is in a "stable" condition and there is "no cause for concern" over his health, the private Indian hospital to where he was admitted said on Friday.
"He is stable, there is no cause for concern," Lilavati hospital spokesman Mohan Rajan told AFP.
"The tests are beginning today," he added, but gave no further details.
The 73-year-old spiritual leader was taken to hospital in India's financial hub on Thursday after suffering from exhaustion and complaining of "discomfort in his abdomen," according to his office.
The Dalai Lama fled to India in 1959 following a failed uprising against Chinese rule over his Himalayan homeland.
In recent weeks he has been pursuing a gruelling travel itinerary as he campaigned for improved human rights in Tibet while China readied to host the Olympic Games in Beijing that ended on August 24.
Violent protests against Chinese rule broke out across Tibet in March, sparking a heavy Chinese crackdown that has drawn global condemnation.
His office said that his medical condition had forced him to cancel all appointments for three weeks, including planned visits to Mexico and the Dominican Republic.