A new report has shed some light on the mystery that is Demi Moore's hospitalization earlier this week. A source reportedly told TMZ that Moore had a bad reaction to inhaling nitrous oxide, popularly known as whippits, whippets, or whip-its.

A friend of Demi's claims the actress lapsed into semi-consciousness and appeared to have a seizure after inhaling the nitrous oxide, which can be found in pressurized whipped cream containers. Pure nitrous oxide can also be purchased as free-standing tanks -- for a price.

The TMZ report pointed out that a whip-it is not a common drug among people of Demi's age and social status. It's typically used by younger people who are looking for a cheap thrill.

Moore's rep had previously cited the cause of her hospitalization as exhaustion -- the favorite catch-all euphemism of publicists desiring to whitewash their clients' nervous breakdowns and substance abuse problems.

Because of the stresses in her life right now, Demi has chosen to seek professional assistance to treat her exhaustion and improve her overall health, Moore's rep said in a statement. She looks forward to getting well and is grateful for the support of her family and friends.

Moore has had a famously difficult year, having split from her husband Ashton Kutcher in November. Earlier in the fall, a woman by the name of Sara Leal claimed to have had an extramarital tryst with Kutcher the weekend of his six-year wedding anniversary.

While Demi tried to maintain a brave face while the couple attempted to save their doomed union, she became noticeably thinner, appearing solo and nearly emaciated at the premiere of Margin Call in October.

Moore was seen out and about with her daughter Rumer two weeks ago: the mother-daughter team reportedly closed down Beacher's Madhouse at the Roosevelt Hotel. She was reportedly drinking Red Bull, and started loosening up and getting into party mode, a while after arriving, according to an onlooker who spoke to People magazine. She seemed really happy to be out with her daughter's friends.

Though her rep did not indicate how long Moore would remain in treatment, it looks like the Charlie's Angels actress is clearing her books for the forseeable future. She had been slated to play Gloria Steinem in the Linda Lovelace biopic Lovelace, but her rep told Entertainment Weekly yesterday that she was pulling out of the role.

On Wednesday, Lovelace producers announced that Chloe Sevigny had signed on to play a feminist journalist in the film -- but not Gloria Steinem specifically.