Demi Moore reportedly hospitalized after inhaling nitrous oxide: What are whippets?

What exactly are whippets? Also known as "whip-its," "whippits," and "nossies," they are steel cylinders filled with nitrous oxide, or "NOX," which is often used in dentists' offices before novocaine injections or dental procedures.

Nitrous oxide is also used in race cars to boost engine power. "So, you know, it's a dangerous substance," Stratyner said.

Inhaling nitrous oxide may cause the user to pass out from lack of oxygen, and may be fatal.

"If you use a lot of it, you're not going to wake up," Stratyner says. He says there is evidence that abusing nitrous oxide causes "dark holes" in the brain, in areas that have been deprived of oxygen and brain cells have been destroyed.