From Business Week:

People who buy prescription medications over the Internet, especially drugs purporting to treat erectile dysfunction, are playing Russian roulette with their lives, a new study contends.

At best the drugs won't help you and at worst they could kill you, the review article said.

Counterfeit Internet drugs are a mushrooming problem. Seizures of fake drugs in Europe quadrupled between 2005 and 2007. And the number of investigations undertaken by the U.S. Food and Drug Administration increased by a factor of eight between 2000 and 2006, according to the study, published in the International Journal of Clinical Practice.

The sale of counterfeit drugs has almost doubled in the last five years, and will hit $75 billion in 2010, according to one estimate, making it one of the more lucrative illicit drug markets.

As many as 2.5 million men in Europe may have taken counterfeit sildenafil (Viagra), the study authors stated.

The problem of fake drugs isn't limited to impotence treatments. According to the study, two pregnant women died after they were given injections of a counterfeit iron preparation for anemia, and 51 children died in Bangladesh of kidney failure after taking paracetamol syrup that was contaminated with diethylene glycol, which is often used as antifreeze in cars.

In 2008, four men in Singapore died after ingesting counterfeit impotence drugs that had been contaminated with a blood-sugar-lowering agent, the study reported.

And bypassing the involvement of a competent doctor means red flags could be missed.

"Erection problems can be an early warning sign of heart disease or diabetes," Jackson said. "If you do have a problem and don't see a doctor, diagnosis of those important conditions can be missed. Men with no symptoms at all who get an erection problem usually are an average of three to five years away from a heart attack. Instead of going to the Internet, they should be going to their doctors to find out if they are at risk and to do something about it.

From the U.S Food and Drug Administration:

The Food and Drug Administration (FDA) is warning the public about a counterfeit version of the weight-loss drug Alli 60 mg capsules (120 count refill pack) being sold over the Internet, particularly at online auction sites.

The counterfeit product is illegal and unsafe. FDA advises people who believe that they have a counterfeit product not to use the drug and to dispose of it immediately. There is no evidence at this time that the counterfeit Alli product has been sold in retail stores.

The counterfeit Alli looks similar to the authentic product, with a few notable differences. The counterfeit Alli has:

• a missing LOT code on the outer cardboard packaging
• an expiration date that includes a MONTH, DAY, and YEAR—the expiration date of the real Alli only contains a MONTH and a YEAR
• a plain foil for the inner safety seal without any words on it—the safety seal of the real Alli has the words “SEALED FOR YOUR PROTECTION” prominently printed on it.
• large capsules with white powder, as opposed to small white pellets found in the real Alli
• a slightly taller plastic bottle with a wider cap and coarser ribbing on the cap than what is seen with the real Alli

Alli is an FDA-approved, over-the-counter weight-loss drug that contains orlistat as its active ingredient. The counterfeit version of Alli does not contain orlistat; instead it is made with varying amounts of sibutramine, a stimulant drug.

Although sibutramine is the active ingredient in another FDA-approved prescription weight-loss drug, it is only to be used in specific doses and under the supervision of a physician.