Demi Moore may have been sent to the hospital after she smoked K2 Spice, a cheap herbal incense that mimics cannabis, experts speculated.

K2 Spice is temporarily illegal under a special order issued by the Drug Enforcement Administration last year. Officials are studying whether it should be made permanently illegal.

Moore, 49, was despondent Monday when a friend called 911 to report the actress was semiconscious.

"She smoked something -- it's not marijuana, but it's similar to incense, and [she] seems to be having convulsions of some sort," a pal is heard telling a 911 operator.

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