CHICAGO — Brenda C. Barnes, the chairman and chief executive officer of the Sara Lee Corp., will take a medical leave of absence, effective immediately, according to the company. Marcel Smits, executive vice-president and chief financial officer, will serve as interim chief executive officer until Ms. Barnes returns.

“We wish Brenda a speedy recovery and look forward to her return,” said James S. Crown, the lead independent director on the board who will assume the role of chairman for Sara Lee. “Out of respect for Brenda’s privacy, we will not be commenting further.”

Mark Garvey will serve as interim c.f.o. He is currently senior vice-president of global business services and corporate controller.

The company also announced the creation of the office of the chairman, which will consist of Mr. Crown, Mr. Smits and Christopher John (C.J.) Fraleigh, c.e.o. of North American Retail and Foodservice. The company said the group has been formed to ensure the continued execution of strategic initiatives and further enhance operational efficiencies.