House Speaker Billy McCoy is in serious but stable condition Wednesday at the University of Mississippi Medical Center in Jackson.
House spokesman Mac Gordon said the 62-year-old lawmaker was moved into intensive care Tuesday.
Doctors on Saturday removed about a foot of one of McCoy's intestines.
The speaker is being treated for diverticulitis, a condition in which small pouches that form in the walls of the intestine become inflamed.
It's not clear how long McCoy will remain in UMC. McCoy has been a member of the House since 1980 and was elected speaker in January. He represents House District 3, which covers Alcorn and Prentiss counties.
Also hospitalized at UMC is Rep. Charlie Capps, who is being treated for pneumonia.
A hospital spokesman said Capps is stable and improving. Capps, 79, has been in the House since 1972. He's a former Appropriations Committee chairman.