Demi Moore was recently released from a Los Angeles hospital following what's been reported as a bender during which the Charlie's Angels actress allegedly did "whip-its," or inhaled nitrous oxide, eventually losing consciousness. The high-profile 49-year-old has been a popular tabloid target in the wake of a messy split with longtime partner Ashton Kutcher. What exactly is a "whip-it" and how dangerous are they?

What is a whip-it?
It's a "perennially popular" way to get high by inhaling nitrous oxide, says The Periscope Post. Users typically use the nitrous oxide canisters that are "used to give store-bought whipped cream its fluff"; hence the name "whip-it." These canisters can be ordered online or bought in kitchen- or restaurant-supply stores. Alternatively, users can inhale nitrous oxide from balloons or bags. "If you were a teenager in the mid-‘90s and you were bored, you may have done them."

What does it do?
You may know nitrous oxide by its more familiar alias: laughing gas. The substance is "usually used by dentists prior to administering Novocaine injections or performing dental procedures," and can result in "euphoric, dissociated, and out-of-body" experiences for people who inhale it, says Test Country. Or, as one anonymous source tells the Guardian: "you get very, very dizzy, light headed and giggly. It lasts about 30 seconds, you stand up and fall down." The high may be brief, says Jane E. Allen at ABC News, but it's also "relatively intense."

Is it legal? 
Technically, yes. Like glue, paint, or VCR cleaners, nitrous oxide is available in most supply aisles, including Wal-Mart's. It's "easily accessible, relatively inexpensive, and generally legal," notes Allen, though most states bar sale of the substance to minors.

How dangerous is it?
The drug works by depriving the brain of oxygen, and evidence suggests that abuse can leave "dark holes" where brain cells have been destroyed, notes CBS News. In terms of side effects, whip-its can cause nausea, vomiting, dizziness, and vitamin B-12 deficiency, which can result in numbness in the fingers and toes. More severe consequences include lung collapse, blood vessel hemorrhage in the lungs, heart attack, seizure, and coma. If that fails to paint a sufficiently vivid cautionary tale, remember this, says the Guardian: "it kills rats."

Sources: ABC NewsCBS News, GuardianNY MetroPeriscope Post, Test Country