An obscure hallucinogenic herb from Mexico is gaining a toehold in the world of recreational drugs, prompting United States law enforcement officials to increase their scrutiny of the plant, which is legal.
Health experts have issued cautions about the drug, which induces jarring effects that are not fully understood.
The herb, Salvia divinorum, is a type of sage that can cause intense hallucinations, out-of-body experiences and, when taken in high doses, unconsciousness and short-term memory loss. Users have also reported sensations of travelling through time and space, assuming the identities of other people and even the feeling of merging with inanimate objects.
Scientists are still unclear about precisely how it interacts with the brain, how it may affect the rest of the body or if it has long-term side effects.
"We don't know how it works," said Dr Ethan Russo, a neurologist in Montana who studied Salvia divinorum for his book, Handbook of Psychotropic Herbs (Haworth Press).
"People who are arbitrarily using it need to be cautious," he said. "It's totally different from anything they may have tried."
The herb can be smoked or chewed. Its leaves can also be boiled to make an intoxicating tea. And unlike most hallucinogenic substances, it is legal in the US, although drug enforcement officials say they are monitoring it closely.
"It's not currently controlled and we're collecting information on it," said Ms Rogene Waite, a spokeswoman for the Drug Enforcement Administration.
Precise facts about the plant - also known as Maria Pastora and diviner's sage - its use and proliferation are almost impossible to gather. It is available almost exclusively over the Internet. No reports of health problems or hospitalisations have been made that may be attributed to the plant. But users and sellers say its popularity is growing.
Users dismiss the concerns, saying no evidence of an addictive quality has been documented and the Mazatec Indians, in Oaxaca, Mexico, have used it, with no apparent ill effects, for centuries.
The New York Times