A federal appeals court told the Drug Enforcement Administration on Friday to restudy its opposition to the therapeutic use of marijuana.

A three-judge panel of the U.S. Circuit Court of Appeals for the District of Columbia said it was concerned that the drug agency may be using inappropriate criteria in determining that marijuana has no legitimate medical use.Kevin Zeese, a lawyer for the National Organization for the Reform of Marijuana Laws (NORML), called the ruling "a major victory."

"We are pleasantly surprised. It's an opportunity for the DEA to do the right thing," Zeese said. He accused the agency of having been "consistently unreasonable" in its past insistence that marijuana has no therapeutic value.

At issue in the legal dispute is how marijuana is classified under the federal Controlled Substances Act. Currently, it is classified as a Schedule I drug, subject to the most severe restrictions on access by doctors and patients.

NORML and other groups have been trying to have the drug's classification under the law switched to Schedule II, which covers substances that have a high potential for abuse but also have "a currently accepted medical use in treatment in the United States."

Lawyers for NORML and the Alliance for Cannabis Therapeutics told the appeals court that marijuana has medical uses for the treatment of cancer, glaucoma and other diseases - and therefore wrongly is classified as a Schedule I drug.

In cancer treatment, some doctors have said marijuana would be the best treatment for the nausea that may accompany chemotherapy.