If you've ever been tempted by commercials offering deep discounts on popular drugs like Viagra or Cialis, you'll want to hear what the I-Team uncovered.

Many people think they are ordering from a legitimate Canadian pharmacy, but that is not often the case. It is not even close.

The I-Team tracked how the dangerous and sometimes deadly counterfeit prescription drug trade makes its way from global markets into St. Louis.

In a filthy Chinese warehouse, it's not hard to miss the fungus growing up and down the walls where counterfeiters produced fake Viagra.

U.S. Customs agents and counterparts around the world are stepping up enforcement and aggressively pursuing counterfeiters trying to sell everything from erectile dysfunction drugs to common antibiotics.
In one raid, investigators found a pill compression machine next to a toilet.

Authorities also found industrialized paint used to give fake Viagra its blue color.

Brian Donnelly, a former FBI agent, is now the Director of North American Security for Pfizer.

"When you push the button and order something online you are playing Russian roulette," said Donnelly.

Lab tests showed some confiscated fakes contained toxic ingredients like boric acid, floor wax, dry wall, and even rat poison.

"Almost everybody who buys medication online thinks they are getting the real product and thinks they are getting a deal. The problem is they don't know what they're getting," said Donnelly.

Donnelly showed NewsChannel 5 some recently confiscated drugs at the company's St. Louis campus.

"We've seen as many as 50 of our products counterfeited in more than 100 countries around the world," said Donnelly.

But Pfizers' Viagra is the number one counterfeited drug on the planet, accounting for 80 percent of global seizers last year.

Experts say the fakes are often hard to spot. They're often darker looking pills with crisp writing. They come in what appears to be authentic packaging complete with a phony hologram.

Jim Gray is the Director of Pharmacy for Barnes Jewish Hospital and spent six years on Missouri's Board of Pharmacy. We sought him out as an independent authority on whether drug companies are exaggerating the problem because counterfeiters are cutting into their profits by an estimated $75 billion a year.

Gray said the counterfeit drug market is a big public health concern and the process typically begins with rogue websites.

"Some place in Southeast Asia, the easiest thing for them to do is put a Maple leaf on their site because everybody in America thinks we all can buy cheap drugs in Canada," he said.

Lab results on some counterfeits found too little active ingredient, while others contained too much.

"I can think of one instance where it was a diabetic medication and the amount of drug was six times the labeled amount and there were a number of deaths," said Gray.

Gray points to another case involving customers who thought they were buying Ambien, a popular sleeping pill.

"What the drug actually contained was Haldol, which is a very very potent antipsychotic that has a lot of side effects," he said.

Authorities have found counterfeit drugs in St. Louis as well. Just last February, 48-year-old Mark Hughes admitted to operating a business called Canada Drug in St. Louis County. He sold thousands of tablets of fake Viagra and Cialis that he purchased from sources in India and China. He is now serving 46 months in prison.

Not all foreign on-line pharmacies deserve a bad reputation, but none of them are FDA approved or inspected.

Experts say to ensure U.S. safety standards, order from a website that has a blue oval VIPPS seal of approval on it, and confirm that site has been approved by The National Association Boards of Pharmacy.

If you think you may have purchased counterfeit medication, contact the drug company that makes the product. They may test it for you.