Players in competitions recognized by the committee are subject to the World Anti-Doping Code, which spells out the rules for drug testing and investigations. There is also a “Prohibited List,” an expansive catalog of banned substances that includes anabolic steroids, hormone modulators and diuretics.

The federation was recognized by the International Olympic Committee in the 1990s, making it subject to the antidoping rules. The recognition brought “the great sport of bridge at the same level with those sports already admitted in the Olympic Games,” the federation said on is website.

“People subject to the code have to be careful about what substances they put into their body,” Mr. Harris said. “If someone is giving him supplements, he ought to be checking what’s in that.”

This standard is controversial in the bridge community, however, where some players wonder why they have to be tested for drugs that would not even help them win, said Alvin Levy, the first vice president of the federation. On an internet forum for bridge players, hundreds of comments were posted, with some saying that drug testing for bridge players made no sense.

Bridge competitions are long events that require focus and stamina, Mr. Levy said. Some competitions can last weeks, and a single event can last several days.

“Many of the top players treat it like they are an athlete,” he said. “They’re very careful what they eat between games. They want to make sure they’re alert. They’ll keep away from alcohol.”

Mr. Levy said that, generally speaking, using drugs to enhance performance is not a pervasive problem in bridge and that he could not recall a previous suspension related to a failed drug test.