NEW YORK (CNN) — Secretary of State Hillary Clinton was treated with blood thinners on Monday at a New York hospital to help dissolve a blood clot in her head and doctors were confident she would make a full recovery.

Clinton was admitted to New York Presbyterian Hospital on Sunday due to the clot that was discovered during a follow-up exam related to a concussion she suffered this month, her spokesman, Philippe Reines, said.

The clot was located in the vein between the brain and and the skull behind Clinton’s right ear and did not result in any stroke or neurological damage, her doctors said in a statement.

Clinton was treated with blood thinners to help dissolve the clot and would be released once the medication dose had been established, they said.

“In all other aspects of her recovery, the secretary is making excellent progress and we are confident she will make a full recovery. She is in good spirits, engaging with her doctors, her family, and her staff,” Clinton’s doctors said.

Clinton, 65, was suffering from a stomach virus earlier this month when she fainted because of dehydration, causing the concussion.

Blood clots “are clumps that occur when blood hardens from a liquid to a solid,” according to the National Institutes for Health.

Clots can form inside veins or arteries or even the heart, the NIH says. “A blockage in the vein will usually cause fluid buildup and swelling,” the NIH website says. Among the possible threats: Sometimes, a “clot can break loose and travel from one location in the body to another.”

Clinton spent the holidays with her family last week after working from home.

She was scheduled to return to work at the State Department this week after being sidelined for most of the past month.

Her illness forced her to bow out of testifying on December 20 before the House Foreign Affairs Committee on the deadly September attack on the U.S. diplomatic compound in Benghazi, Libya.

Clinton, a one-time presidential candidate who is the source of constant speculation she might run again in 2016, plans to step down from the State Department once a replacement is confirmed by the Senate.