If you’re looking for a little help shedding extra pounds after the holidays, the government is warning you to stay away from nearly 30 weight-loss products that contain unlisted and possibly dangerous ingredients.

The pills are advertised as “natural” fat busters and have intriguing names like Imelda Perfect Slim and Zhen de Shou. Some suggest they are innovative “herbal” remedies from Asia.

But the Food and Drug Administration on Monday said the concoctions contain unlisted ingredients, including powerful appetite-suppressing drugs and a suspected carcinogen.

“These tainted weight loss products pose a great risk to public health because they contain undeclared ingredients and in some cases prescription drugs in amounts that greatly exceed their maximum recommended dosages,” said Dr. Janet Woodcock, who directs the FDA’s drug evaluation center.

FDA lab testing found 28 dietary supplements that could land unsuspecting users in the emergency room.

Many contain sibutramine, a powerful appetite suppressant that’s a chemical cousin of amphetamines. It can cause heart attacks, strokes, heart palpitations and other problems. Some contain phenolphthalein, a chemical long used as a laxative, but which is now being withdrawn from the market because of cancer risks.

None of the supplements lists the dangerous ingredients on the label. “Consumers have no way of knowing that these products contain powerful drugs that can cause serious health consequences,” Woodcock said.

The FDA is considering criminal charges against some of the companies, because they have not responded to requests for recalls.

The products are: atloss Slimming, 2 Day Diet, 3x Slimming Power, 5x Imelda Perfect Slimming, 3 Day Diet Japan Lingzhi, 24 Hours Diet, 7 Diet Day/Night Formula, 7 Day Herbal Slim, 8 Factor Diet, 999 Fitness Essence, Extrim Plus and GMP.

Also: melda Perfect Slim, Lida DaiDaihua, Miaozi Slim Capsules, Perfect Slim, Perfect Slim 5x, Phyto Shape, ProSlim Plus, Royal Slimming Formula, Slim 3 in 1, Slim Express 360, Slimtech, Somotrin, Superslim, TripleSlim, Zhen de Shou, Venom Hyperdrive 3.0