Uh-oh, Bumbo.

The South African maker of molded foam seats that help babies sit up is recalling about 4 million of the chairs because of safety problems.

Babies can get hurt falling out of the seats.

If you have one of the Bumbo seats, you don't have to throw it out or return it. Instead, the recall works a little like one for a car. Bumbo International Trust has a free fix that consists of a safety belt to keep kids in place.

You have to get those from the company, not the store where you bought the seat.

Bumbo's repair kit also includes a warning sticker to remind parents and caregivers not to use the seat on raised surfaces, such as tabletops.

Don't use the seats until they're fixed, the company and the Consumer Products Safety Commission say.

Back in 2007, Bumbo recalled 1 million of the seats after reports of serious head injuries to kids who fell out of seats. Three children whose chairs were on top of tables suffered skull fractures. The recall consisted of a warning and beefed-up instructions against using the seats above the floor or ground.

The CPSC and Bumbo now say babies have fallen from chairs atop elevated surfaces at least 50 times since the 2007 recall. In 19 cases, the kids reportedly sustained skull fractures. There have been other reports of kids being injured after getting out of seats at floor level or unknown heights.

The latest recall affects seats bought between between August 2003 and this month. They've been sold by some of the biggest retailers, including Wal-Mart, Target, Babies "R" Us and Sears.

For more details, including a video on how to repair the seats, see the Bumbo USA recall website.