Lt. Gov. Amy Tuck has been hospitalized for nausea and severe headaches, The Associated Press learned.
Senate President Pro Tempore Travis Little told the AP on Tuesday that Tuck was admitted to the University of Mississippi Medical Center on Saturday. Doctors were still performing tests Tuesday to diagnose her condition.
It wasn't clear when Tuck, 41, would be released or when she would return to the Capitol.
The session is set to end May 9, and lawmakers are about to enter one of their most critical periods of work - final budget negotiations that must end by May 1.
Tuck typically is actively involved in House-Senate budget talks. Her continued absence was not explained during Tuesday's session.
Little said he spoke to Tuck by phone Monday and Tuesday after the Senate had finished its daily work.
"She seemed interested in what was going on,'' Little said.
Tuck is in her second term, having originally taken office in January 2000. She rarely misses a day at the Capitol.
Tuck was first elected as a Democrat but switched to the Republican Party in December 2002. She won her second term as a Republican.
She served as a state senator from Maben from 1990-95 and ran unsuccessfully for secretary of state in 1995.
She was secretary of the Senate, the chamber's top administrative officer, from 1996-99.
Tuck spokesman Joseph Ammerman said the lieutenant governor was not feeling well last week.
Tuck presides over the Senate and keeps a busy schedule, often accepting outside speaking engagements before and after work hours at the Capitol.
She was a no-show Monday when Gov. Haley Barbour and about 100 lawmakers and other officials honored retired House Speaker Pro Tempore Robert Clark, for whom a building was named. Tuck had been scheduled to speak at the ceremony.