The maker of the popular Bumbo baby seat is issuing a voluntary recall of more than 4.6 million of the foam mini-chairs.
The move follows reports about scores of injuries, including skull fractures, the company says.
Consumers should stop using it until they install a free repair kit, which includes a restraint belt and a new warning sticker, and never use the Bumbo seat on an elevated surface, the South Africa-based firm, Bumbo International Trust, said.
Owners of the Bumbo in Hong Kong should e-mail info@bumbo.  com for details on how to obtain the safety kit.
The warnings were echoed by the United States Consumer Product Safety Commission and Health Canada.
The recall involves about 4.3 million Bumbo seats in the US and about 340,000 in Canada, as well as an unknown number sold elsewhere.
Since 2007, at least 50 US incidents have been reported in which babies fell, while the moulded-foam seat was on a raised surface.
Nineteen of the incidents included skull fractures, the firm and the product safety commission said.
Another 34 reports have been received of infants hurt, while the one-piece seat was on a floor or an unknown elevation. Two babies suffered fractured skulls.
Five incidents were reported in Canada, with three minor injuries, Health Canada said.