Former basketball star Lamar Odom continues to cling to life in a Las Vegas hospital after he was found unconscious at the Bunny Love Ranch brothel Tuesday afternoon. Reports are circulating about possible drug use, but they have not been confirmed. However, it is believed he was taking a large amount of so-called herbal Viagra at the time before he was found. 

According to E! Online, Dennis Hof, owner of the Bunny Love Ranch where Odom was found, said he didn't believe Odom was doing any illegal drugs, but he was taking "herbal Viagra," an unauthorized equivalent of Pfizer's prescription drug that can be purchased easily at many convenience stores.

"Of course everybody's thinking, 'Well, maybe it was drugs.' We didn't see any effects of that," Hof said. "He was going to sleep every night, and I don't think he was doing any drugs — although you never can tell. He was doing 'herbal Viagra' and a lot of it."

"Herbal Viagra" works to treat erectile dysfunction by increasing blood flow, just as real Viagra does.

Dr. Todd B. Nippoldt of the Mayo Clinic warns that people should proceed with caution with any product that claims to be a natural form of Viagra. He said several "herbal Viagra" products could contain small amounts of prescription medications, which can be dangerous to take. 

"Herbal supplements aren't held to the same standards as prescription and over-the-counter medications — so it can be difficult to know which ones are safe or effective," he said. 

A 2013 Associated Press article reported that "herbal Viagra" has a hidden threat for people on heart or blood pressure medications. Taking just one pill could be enough to cause heart attack or stroke if it's mixed with nitrates used to treat blood or heart conditions.

In March, the U.S. Food and Drug Administration put out a public notification advising people not to use a product called Herb Viagra because it contained sildenafil. Sildenafil (Viagra's scientific name) is used to treat erectile dysfunction and it could interact with certain prescription medications and could lower blood pressure.

Odom has a past history of drug abuse, but it's unknown if he has any heart conditions. Sources told TMZ that Odom was believed to have been taking eight to 10 "herbal Viagra" pills at a time during his stay at the legal brothel. Witnesses at the hospital added that Odom had cocaine in his system, as well as track marks on his arms. They also said doctors have said there's fluid in his lungs from the cocaine use.

E! Online is also reporting that Odom is being treated for an overdose. A source added that "virtually every drug imaginable was found in his system." Odom could have brain damage and remains unconscious on a ventilator.