NFL: Eating too much meat abroad may lead to positive test

— -- NFL players are being warned about consuming meat produced in China and Mexico that potentially contains clenbuterol, which is banned under the league's performance-enhancing substance policy.

The drug-testing program's independent administrator sent a memo to players, saying "consuming large quantities of meat while visiting those particular countries may result in a positive test."

Clenbuterol is a muscle-building and weight-loss stimulant.

"Players are warned to be aware of this issue when traveling to Mexico and China," the memo read. "Please take caution if you decide to consume meat, and understand that you do so at your own risk."

The drug-testing program again advised: "Players are responsible for what is in their bodies."

The Oakland Raiders will face the Houston Texans on Monday Night Football on Nov. 21 in Mexico City as part of the league's international series. The Raiders also hosted a fan fest as part of the NFL draft this past Saturday in Mexico City.

Texans left tackle  Duane Brown actually tested positive for clenbuterol last season after a bye-week trip to Mexico during which he ate Mexican beef, sources told ESPN.

After a months-long process, Brown was finally cleared in April, sources said, allowing him to avoid what would have been a 10-game suspension. His case offers a warning for other players.

Several players, including Arizona Cardinals defensive back Patrick Peterson, took to Twitter after the memo was sent out.

Information from ESPN.com's Tania Ganguli and Dan Graziano contributed to this report.