The weight loss supplement sold under the name Que She and marketed as "an all-natural blend of Chinese herbs" contains not only fenfluramine, a stimulant withdrawn from the US market in 1997 after studies showed it caused serious heart valve damage, but also three other potentially harmful drugs.
The other drugs found in Que She were the beta-blocker propranolol, which can harm people with asthma and certain heart conditions; prescription weight loss drug sibutramine, which has been linked with increased risk of heart attack and stroke in patients with a history of heart disease; and the stimulant ephedrine.
The drugs in Que She could be dangerous on their own in certain groups of patients, and could "interact with other medications and result in a serious adverse event," the FDA warned, urging anyone who has taken the weight loss supplement to consult a health care professional.
The Diet Spotlight website described Que She as a compound of 11 Chinese herbs that "purportedly helps a person lose weight by suppressing appetite and increasing metabolism."
Several websites that sold the slimming aid had removed Que She from the list of products they sell shortly after the FDA issued its warning on Thursday.