WASHINGTON - Ephedra makers came under attack in Congress recently with a prominent lawmaker calling their conduct unacceptable and threatening tougher regulation of the controversial diet supplement.

　　"If they don't clean up their act, I can promise you we will do it for them," Rep. Billy Tauzin, a Louisiana Republican, told a House Energy and Commerce subcommittee hearing. Tauzin chairs the full committee.

　　"We've learned that these ephedra supplement makers have been engaged in some highly questionable behaviour, from producing products without any safety testing to promoting safety and efficacy based on dubious industry-sponsored studies," Tauzin said.

　　Government officials have warned consumers not to take the stimulant and proposed a warning label for ephedra products that mentions heart attack and death as possible side effects.

　　Consumer groups say ephedra, an herb promoted for weight loss, is too dangerous and have called for a ban.

　　Ephedra makers insist the product is safe when taken as directed; but one manufacturer, privately-held Metabolife International, said in a statement it supports the proposed warning label.

　　Metabolife said it had acted responsibly in marketing its product, Metabolife 356, which comes with a warning advising people with problems such as heart disease to consult a doctor before use.

　　"It is not for everyone, as we clearly state on our label," Metabolife Chief Executive Russell Schreck told the committee.

　　Metabolife also said ephedra had helped many people battle obesity, a major US health problem.

　　"Millions of consumers throughout the United States use ephedra dietary supplements as safe, inexpensive and effective means by which to support weight loss," the company said.

　　Two former Metabolife executives, Michael Ellis and David Brown, and one current employee, Daniel Rodriguez, invoked their constitutional right against self-incrimination and declined to testify.

　　The Justice Department announced last August it had launched a criminal investigation to find out if Metabolife lied about whether its ephedra product killed anyone or made them sick. The company has denied wrongdoing.

　　Unlike drugs, supplements including vitamins and herbs are not required to pass tests for safety and effectiveness before being sold.

　　Health and Human Services Secretary Tommy Thompson said the Food and Drug Administration was "somewhat hampered" by current law in policing supplements.

　　Thompson, speaking to reporters at an unrelated event, said it was time to require supplement makers to turn over to the government any complaints from consumers reporting health problems, as drug makers must do.

　　The debate over ephedra intensified after the February death of professional baseball player Steve Bechler. A Florida medical examiner ruled ephedra contributed to Bechler's death.