Mimi Trieu peddled diet pills. But instead of weight loss, her customers got possible carcinogens and illegal drugs, authorities say.

Trieu, 46, of Philadelphia, pleaded guilty today to an 18-count indictment charging her with the illegal importation and distribution of more than 4 million diet pills that contained a controlled substance, unapproved drugs and a possible carcinogen, U.S. Attorney Zane D. Memeger announced.

Trieu owned Hong Kong Beauty International, which was located at 5520 Whitaker Ave. and was in the business of importing and distributing various beauty products, including diet pills. Trieu pleaded guilty to mail fraud, conspiracy to smuggle illegal merchandise and distribution of Sibutramine, a controlled substance. A sentencing hearing is set for March 10. Trieu faces up to  243 years in prison and a $4.5 million fine.

Trieu imported and sold diet pills between October 2008 and May 2009, according to Memeger's office. She continued to import the pills until last March, even after learning that the capsules contained Sibutramine and other dangerous substances, and that the pills weren't approved by the Food and Drug Administration. The FDA had warned consumers that, besides Sibutramine, the drugs contained an anti-seizure medication and a chemical solvent that may be a carcinogen. According to the FDA, these drugs could cause serious side effects including nausea, vomiting, elevated blood pressure, heart attacks and strokes.

Trieu smuggled the diet pills from China through the mail, using packages with customs declarations that falsely described the capsules as "gifts" worth minimal amounts, according to Memeger's office. She also wrongly advertised that the illegal diet pills contained natural ingredients. She told some customers the drugs were made in Japan, and told one customer the FDA warning was untrue.

The case was investigated by the FDA's Office of Criminal Investigations, the U.S. Postal Inspection Service, and U.S. Immigration and Customs Enforcement Homeland Security Investigations. It is being prosecuted by Assistant U.S. Attorneys Judy Goldstein Smith and Sarah L. Grieb.