President George H.W. Bush nominated Thomas in 1991 to fill the seat that had been held by Associate Justice Thurgood Marshall.
Thomas, who is 73 and the only African American on the Supreme Court, was previously a judge on the U.S. Court of Appeals for the District of Columbia Circuit.
Several of the justices have had health run-ins during this term, mainly due to the coronavirus pandemic. Associate Justice Brett Kavanaugh tested positive for COVID-19 days before the justices returned to the courtroom in the fall. In November, Associate Justice Neil Gorsuch called in sick with a stomach bug.
The extent of Thomas’ symptoms was not clear.
The Supreme Court is set to hear oral arguments on Monday. Court officials said Thomas intends to take part in considering cases through court records and recordings of oral argument for the days he cannot be there in person or remotely.
What is Clarence Thomas Famous For?
Clarence Thomas is the second black justice and the only one currently sitting on the bench. As a Supreme Court justice, Clarence Thomas is famous for his lack of questions during oral arguments.