The Food and Drug Administration said the maker of the dietary supplement has agreed to recall 14 Hydroxycut products. Available in grocery stores and pharmacies, Hydroxycut is advertised as made from natural ingredients. At least 9 million packages were sold last year, the FDA said.

    Dr. Linda Katz of the FDA's food and nutrition division said the agency has received 23 reports of liver problems, including the death of a 19-year-old boy living in the Southwest. The teenager died in 2007, and the death was reported to the FDA this March.

    Other patients experienced symptoms ranging from jaundice, or yellowing of the skin, to liver failure. One received a transplant and another was placed on a list to await a new liver.

    There was no immediate comment from the U.S. distributor of the diet pill, Iovate Health Sciences, headquartered near Buffalo, N.Y. Made by a Canadian company, Hydroxycut is used by people trying to shed pounds and by body builders to sharpen their muscles.

    Dietary supplements aren't as tightly regulated by the government as medications. Manufacturers don't need to prove to the FDA that their products are safe and effective before they can sell them to consumers. But regulators monitor aftermarket reports for signs of trouble, and in recent years companies have been put under stricter requirements to alert the FDA when they learn of problems.

    Katz said it has taken so long to get a handle on the Hydroxycut problem because the cases of liver damage were rare and the FDA has no authority to review supplements before they're marketed. "Part of the problem is that the FDA looks at dietary supplements from a post-market perspective, and an isolated incident is often difficult to follow," she said.

    The FDA relies on voluntary reports to detect such problems, and many cases are never reported, officials acknowledge.

    Health officials said they have been unable to determine which Hydroxycut ingredients are potentially toxic, partially because the formulation of the products has changed several times. A medical journal report last month raised questions about one ingredient, hydroxycitric acid, derived from a tropical fruit. The article said it could potentially damage the liver.

    美國食品和藥物管理局稱，生產商已同意回收14種減肥藥。這種產品在雜貨店和藥店裏都可以買到.據稱,14種減肥藥是由天然原料製成的。去年至少有9萬包已經售出.

    食品及藥物管理局的食品和營養司的琳達卡茨醫生表示,該司已收到23份反映肝髒損害的報告，其中包括居住西南地區19歲男子2007年死於肝髒衰竭。並於本年3月報告到食品及藥物管理局.

    其他病人的症狀，包括黃疸，皮膚發黃
，肝功能衰竭。其中一人接收了肝功移植,另一人被列在等待移植的名單裏.

    美國減肥藥分銷商對此沒有立即發表評論,總部設在紐約水牛城附近，藥品是由加拿大公司生產.這種藥品是用來迅速減輕體重,增強體力.達到健美的目的.

    藥品並沒有受到政府的嚴格限製。製造商並不需要向美國食品及藥物管理局說明他們的產品是安全和有效的,才cai可ke以yi出chu售shou給gei消xiao費fei者zhe。但dan監jian管guan機ji構gou監jian測ce到dao了le售shou後hou的de麻ma煩fan問wen題ti，並bing在zai最zui近jin幾ji年nian公gong司si一yi直zhi在zai實shi行xing更geng嚴yan格ge的de要yao求qiu
，提ti醒xing美mei國guo食shi品pin和he藥yao物wu管guan理li局ju當dang他ta們men了le解jie的de問wen題ti。

    卡茨說，花費了很長時間才處理完減肥藥的問題
，因為該案件是罕見的肝損害,在銷售該藥品之前,美國食品及藥物管理局又沒有權力審查. “美國食品及藥物管理局著眼於了解消費者的反映
，個別案件往往被忽略了。”

    美國食品及藥物管理局是通過顧客的反映才能發現問題，但是,許多情況下，此類案件從來沒有報道過,官員承認。

    衛wei生sheng官guan員yuan表biao示shi，他ta們men一yi直zhi無wu法fa確que定ding哪na些xie減jian肥fei藥yao可ke能neng含han有you毒du成cheng分fen
，部bu分fen原yuan因yin是shi產chan品pin工gong藝yi流liu程cheng改gai變bian了le好hao幾ji次ci。上shang個ge月yue醫yi學xue雜za誌zhi報bao對dui羥qiang基ji酸suan提ti出chu了le異yi議yi，它ta取qu自zi熱re帶dai水shui果guo,有可能會損害肝髒,文章說.