A recent study showing that marijuana can be an effective painkiller has promoted an advocacy group to challenge federal rules that state that the drug has no accepted medical use.

The Associated Press reported Feb. 22 that Americans for Safe Access, a medical-marijuana advocacy group, is suing the U.S. Department of Health and Human Services (HHS) and its subsidiary agency, the U.S. Food and Drug Administration (FDA). The lawsuit, filed in U.S. District Court, says that HHS has engaged in "arbitrary and unlawful behavior" and prevented "sick and dying persons from seeking to obtain medicine that could provide them needed, and often lifesaving relief."

"The FDA position on medical cannabis is incorrect, dishonest and a flagrant violation of laws requiring the government to base policy on sound science," said Joe Elford, the lawyer for Americans for Safe Access.

Because the federal government says marijuana has no legitimate medical use, users in states that have passed medical-marijuana laws are still subject to arrest and prosecution under federal drug laws.

In a study published last week in the journal Neurology, researchers from the University of California at San Francisco reported that HIV patients given marijuana suffered less pain than a group of patients who received placebos.