Palestinian prime minister Salam Fayyad was in hospital for an inflamed pancreas on Tuesday, a medic in Ramallah said, having been admitted the night before with stomach pains.
"Medical tests and scans show that Fayyad is suffering from pancreatic inflammation," a doctor at the hospital in the West Bank city told AFP.
But his condition was "not serious," the doctor said, adding he would likely leave the hospital after undergoing treatment and resting.
The 61-year-old, a smoker who suffered a heart attack during a private visit to the United States in May 2011, could be kept at the hospital overnight for observation, the source added.
A former senior official at the International Monetary Fund, Fayyad is an economist who won respect for cleaning up the finances of the Palestinian Authority and improving security in the West Bank.
He has headed the Palestinian government since June 2007, after the Islamist Palestinian movement Hamas seized control of the Gaza Strip.
Rumours have been swirling in the past few days that Fayyad is to be removed from the post following a dispute with the nationalist Fatah movement of Palestinian president Mahmud Abbas.
Faced with chronic budget problems, the Palestinian Authority is currently going through one of its worst financial crises since its formation in 1994.