He warned, though, that there could be health concerns if it were taken along with antidepressants — a combination he said could cause hypertension, high blood pressure or strokes.
And there is always the danger of "merging," when a person using the drug feels the need to merge with another object.
"You may try to merge with an open window and fall out," he said.
A DEA spokeswoman said the administration does not comment on the specifics of its consideration of substances while they are under review. At the Food and Drug Administration, which also must review a substance before it is put on the controlled substances list, two spokeswomen said they had no record of any study being under way.
The DEA Diversion Control Program has included salvia divinorum on its list of Drugs and Chemicals of Concern, and in a statement about the herb compares the active ingredient it contains to that in absinthe and to THC, which is found in marijuana.
"There has been a growing interest among young adults and adolescents to re-discover ethnobotanical plants that can induce changes in perception, hallucinations or other psychologically-inducing changes," the statement said. "Since Salvia Divinorum is not specifically listed in the Controlled Substances Act, many on-line botanical companies and drug promotional sites have advertised Salvia as a legal alternative to other plant hallucinogens like mescaline."
Richard Glen Boire, an attorney with the Center for Cognitive Liberty and Ethics, said salvia divinorum "does not meet the criteria" to be a Schedule 1 substance. "It does not have the abuse potential that other drugs that are on the DEA's list of controlled substances," he said.
The group submitted a report to the DEA in October to make the case to keep salvia divinorum legal, which included a survey of hospital emergency room data from across the country which found no record of anyone requiring treatment from using the herb.
Spokesmen at the Center for Substance Abuse Research and the Community Epidemeology Work Group, two drug abuse watchdog groups, said concerns about the herb have not been raised with their organizations.
Ethan Russo, a clinical neurologist and expert on psychotropic drugs who has studied the herb, said there is no evidence that salvia divinorum causes any damage to the brain and he does not want to see it outlawed, saying that could inhibit study of the drug.
"I can say that there is no inherent danger to salvia divinorum except that some people are going to scare themselves and it's possible for someone to walk off and get hurt by something like falling down a flight of stairs, so somebody should always be close by," he said.
"I see no reason for this to be rendered illegal," he continued. "It's not going to help anything. In a perverse way, if it were rendered illegal it might make it more attractive to some people. … There is a long list of substances on the DEA list and they haven't been eradicated."
Halpern, who emphasized that he is not a drug advocate, said he doesn't believe that making salvia divinorum illegal is necessary, though he also said there is no reason for anyone to fear that DEA scheduling would interfere with academic research.
"If it is scheduled, I don't think it's going to change anything," he said. "It doesn't seem like there's going to be that many repeat users."