(CBS) With a handful of teams hosting joint practices in the preseason, the NFL recently sent out a reminder to clubs to be careful of their actions and avoid fighting.

We found out just why that was Tuesday, when a joint practice between the Rams and Cowboys got really ugly. Several brawls broke out with dozens of players involved, and the fight spilled along the sideline right next to fans, with only a small fence separating them.

The rest of the Cowboys-Rams practice was called off.

“We’re going to have to continue to emphasize that stuff is not what we want,” Cowboys executive vice president Stephen Jones said. “It should not be a part of our game. It’s not good for either team. Obviously, there are huge injury risks. We’ve just got to learn from it. I’d hate to think two teams can’t get together.

Take a look at the video below.

Cowboys receiver Dez Bryant took his helmet off during the brawl and was hit in the face.

The Bears are among the teams participating in joint practices, as they’re in Indianapolis to work against the Colts on Wednesday and Thursday before a game Saturday.