Corning Inc has won US approval to buy a division of Becton Dickinson & Co that makes specialised labware for $720 million.
The US Federal Trade Commission though said Corning must help Sigma-Aldrich Co enter the market.
Corning agreed to provide assets and assistance to Sigma-Aldrich Co so it can begin manufacturing containers such as dishes for culturing cells and other containers, the FTC said.
Corning will supply the products to Sigma-Aldrich until its manufacturing plant is up and running.
Corning and the Becton Dickinson division being purchased are the largest suppliers of specialised dishes used by researchers in cell culture work. There are two smaller providers, and the arrival of Sigma-Aldrich into the market would restore competition, the FTC said.