A Wisconsin judge on Friday ordered Anheuser-Busch to stop suggesting in advertising that MillerCoors’ light beers contain corn syrup, wading into a fight between two beer giants that are losing market share to small independent brewers.

U.S. District Judge William Conley for the Western District of Wisconsin granted a preliminary injunction sought by MillerCoors that temporarily stops Anheuser-Busch from using the words “corn syrup” in ads without giving more context.

MillerCoors sued its rival in March, saying St. Louis-based Anheuser-Busch has spent as much as $30 million on a “false and misleading” campaign, including $13 million in its first commercials during this year’s Super Bowl. The ad showed a medieval caravan pushing a huge barrel of corn syrup to castles for MillerCoors to make Miller Lite and Coors Light. The commercial states that Bud Light isn’t brewed with corn syrup.