Major League Baseball and the National Hockey League have launched investigations into doping claims.

A Florida couple allegedly sold illegal steroids to players from the Washington Nationals and Washington Capitals.

Richard and Sandra Thomas were arrested by police in Polk County, Florida for possession of a reported US dollars 200,000 worth of illegal drugs.

According to both the Tampa Tribune and Washington Times, Richard Thomas claimed to have sold the drugs to professional athletes in several sports, and identified both the Nationals and Capitals.

"We have no reason to believe there is any merit to this story, but the National Hockey League and the Washington Capitals take all such allegations seriously," said Capitals president Dick Patrick in a statement.

"Capitals players have fully participated in the NHL's random drug testing program, and at no point has a Capitals player tested positive. In addition our players have been tested at international events, such as World Championships and Olympics. We welcome and will fully cooperate with the NHL's investigation."

NHL deputy commissioner Bill Daly added: "The Washington Capitals have no knowledge of any aspect of this allegation.

"Capitals players were subjected to no-notice testing five separate times over the past two seasons pursuant to the terms of the Collective Bargaining Agreement and there was no indication of any improper conduct or wrongdoing."

According to Polk County sheriff Grady Judd, Richard Thomas did not identify any individual players when making his claim.

Daly added: "Even though there are no specifics provided in the story and we have no reason, at this point, to believe the allegations are true, the National Hockey League takes all matters of this nature very seriously and will conduct a prompt investigation."

Nationals president Stan Kasten addressed the story prior to today's game against the Mets in New York.

"I don't know anything more about this story than what you have read," Kasten said on the team's website.

"I have spoken to Major League Baseball, and they didn't have any more details. They are working on finding out all they can. I know the NHL is doing the same.

"Until I hear something from MLB, I don't have anything to be concerned about. I haven't been told anything to be concerned about by MLB at all. So, for now, the story is what it is. I don't know any more than that."

Kasten has instructed his players not to comment on the story.

"I have asked my players not to comment on this and go on with the rest of their day as they prepare to play a game," Kasten said.

"I hope all of you can respect their needs of preparing for the game tonight. That was my advice to my team, and I'm sure they will follow up on it."