The lawsuit filed in federal court by Americans for Safe Access accuses the U.S. Department of Health and Human Services of engaging in "arbitrary and unlawful behavior" that prevents "sick and dying persons from seeking to obtain medicine that could provide them needed, and often lifesaving relief."
The Oakland-based advocacy group wants a judge to force the department and the Food and Drug Administration to stop giving out information that casts doubt on the efficacy of marijuana in treating various illnesses.
The lawsuit differs from previous legal efforts to decriminalize marijuana because it seeks to get a federal agency simply to acknowledge that pot can help reduce the symptoms of some conditions.
The change would make it easier for states to develop their own medical marijuana policies, said Joe Elford, chief counsel for Americans for Safe Access. In the past, supporters of medical marijuana have focused on getting the government to stop classifying marijuana as an illegal drug.
"We are not asking the federal government to change what it does about medical marijuana, we are asking them to change what they say about it," Elford said.
The Department of Health and Human Services did not immediately respond to a telephone call seeking comment on the lawsuit.
Besides discouraging people who might benefit from smoking pot, the agency's position bolsters the Drug Enforcement Agency's attempts to crack down on medical marijuana use in states where the practice is legal, he said.
California is one of 11 states where marijuana use is legal for people with a doctor's recommendation. But because the DEA considers pot illegal patients can still be arrested and prosecuted by federal authorities.
Jacqueline Patterson, 28, who moved to California from Missouri so she could get marijuana for a severe stutter associated with her cerebral palsy, said the government's insistence that pot has no medical benefits puts an unnecessary burden on people who get relief from using it.
"It really creates a dual stigmatization in the states that have no protections," Patterson said. "Not only do I have this profoundly humiliating disability, I smoked pot, and my family has been taught the same addictive narcotic story that I had been."
Last week, researchers from the University of California, San Francisco reported in the journal Neurology that a test involving 50 HIV patients showed that those who smoked pot experienced much less pain than those given placebos.
Americans for Safe Access said in the lawsuit that Health and Human Services has rejected its requests to retract the assertion that cannabis "has no currently accepted medical use in treatment in the United States," a position the agency has advertised since 2001.
Countering that statement by petitioning the government and distributing evidence that marijuana eases the symptoms of cancer, multiple sclerosis, HIV and other conditions has cost Americans for Safe Access more than $100,000, the group said in its suit.
Since California voters approved medical marijuana use in 1996, 10 other states have adopted measures protecting qualified patients from state prosecution. They are Alaska, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Rhode Island, Vermont and Washington.