The State Department said an ill Clinton is now recovering at home after the incident, according to the AP.
CBS News' Margaret Brennen reports Clinton was dehydrated from a stomach bug.
The AP reports:
WASHINGTON — The State Department says Secretary of State Hillary Rodham Clinton, who skipped an overseas trip this past week because of a stomach virus, sustained a concussion after fainting.
She's now recovering at home and being monitored by doctors.
An aide, Philippe Reines, says Clinton will work from home next week, at the recommendation of doctors.
Congressional aides do not expect her to testify as scheduled at congressional hearings on Thursday into the Sept. 11 attack against a U.S. diplomatic outpost in Benghazi, Libya, that killed four Americans, including the U.S. ambassador.
The aides spoke on condition of anonymity because they weren't authorized to publicly discuss Clinton's status.
The department says Clinton was dehydrated because of the virus and that she fainted, causing the concussion. No further details were immediately available.
Due to her concussion, Clinton will no longer testify before Congress about the investigation into the deaths of four Americans in the Sept. 11 Benghazi attack. The Hill reports:
Clinton will not testify as scheduled before the Senate Foreign Relations Committee, said Jodi Seth, a spokeswoman for Chairman John Kerry (D-Mass.).
The State Department told Kerry of Clinton's concussion on Saturday morning, and, when he heard, Kerry insisted that she not attend the hearing.
"Senator Kerry was relieved to hear that the secretary is on the mend, but he insisted that given her condition, she could not and should not appear on Thursday as previously planned, and that the nation’s best interests are served by the report and hearings proceeding as scheduled with senior officials appearing in her place," Seth said.
Clinton deputies Tom Nides and Bill Burns will testify in her place, Seth said.