Janet Napolitano, the former head of US Homeland Security and current president of the University of California, has been hospitalized due to side effects caused by her cancer treatments, the university said Tuesday.

Napolitano, a Democrat who is also a former governor of Arizona, has been undergoing treatment for a recurrence of cancer since August, the university said.

The 59-year-old was admitted to an undisclosed hospital on Monday with side-effects from the treatment, spokeswoman Dianne Klein said in a statement emailed to reporters on Tuesday.

"According to her physicians, she is doing extremely well," Klein said in the statement. "They expect her to be discharged in the next day or so and back to her normal duties at full capacity very soon."

The email did not specify the type of cancer nor the hospital where Napolitano is being treated.

The main office of the University of California is in Oakland, not far from the university's flagship Berkeley campus.