products. stiff knights, king of romance, rhino blitz. in studies funded by pfizer which makes viagra, dr. irwin goldstein investigated 5 different brands to see what they contained. >> it was unbelievable are what we found from rat poison to commercial paint to heavy metals. to even drugs that did other things. we found drugs that lowered blood sugar. it just goes to show you the quality of the manufacturing of these is extremely poor. >> reporter: and it's big business. >> unfortunately, a lot of these folks are based overseas. and set up fly-by-night operations. >> reporter: the supplement industry is not as tightly regulated as the drug industry. the fda found these supplements often contain undeclared ingredient, the same ingredient found in viagra. in large dose, it may dangerously lower blood pressure. >> people want this stuff. people don't really care about the warnings when they're faced with the inevitability that they're going to have sexual activity and they may not be