Oracle Co-CEO Mark Hurd is taking a leave of absence from the software giant to deal with an unspecified medical illness.

Hurd, 62, has been serving as co-CEO at Oracle with Safra Catz for five years; they took over from Oracle founder Larry Ellison, who took on the company’s chief technology officer position. Ellison hired Hurd in 2010 as Oracle president after Hurd stepped down from his CEO job at Hewlett-Packard due to a relationship he had with a company consultant.

“Though we all worked hard together to close the first quarter, I’ve decided that I need to spend time focused on my health,” Hurd said in a statement. “At my request, the board of directors has granted me a medical leave of absence.”

Neither Hurd nor Oracle gave any other details about Hurd’s condition, nor did they offer any hints about when he might return.

While Hurd is on leave, Catz will assume all of Oracle’s CEO duties. Hurd has been largely responsible for overseeing Oracle’s sales, marketing, consulting, support and business units.

Oracle made Hurd’s leave of absence known late Wednesday just before it released its fiscal first-quarter results. For the period that ended Aug. 31, Oracle reported earnings, excluding one-time items, of 81 cents a share, on revenue of $9.22 billion.