The government has eased restrictions on Marinol, a byproduct of marijuana that doctors can prescribe to counter some symptoms of AIDS and side effects of chemotherapy.

National Drug Control Policy Director Barry R. McCaffrey said the capsulized form of Marinol is the "safe and proper way" to make a form of marijuana available to the public for medical use.

"This action will make Marinol, which is scientifically proven to be safe and effective for medical use, more widely available," McCaffrey said Friday.

The Drug Enforcement Administration reclassified Marinol from a "Schedule 2" drug to the less restrictive "Schedule 3" category. This means that instead of being classified with drugs like morphine, Marinol is now grouped with more widely used drugs like codeine.

Marijuana is classified as a "Schedule 1" drug and thus cannot be prescribed by doctors.

The change comes as dozens of states are grappling with the issue of legalizing marijuana. Several states, including Oregon and California, have approved the use of marijuana with a doctor's consent.

McCaffrey, who has remained staunchly opposed to those efforts, said Friday's change was the result of "pure science. There's no politics involved."

Marinol is the only agent in marijuana that has undergone research and been developed into a prescription drug. First put on the market in 1985, Marinol has been used to treat anorexia and weight loss associated with AIDS, and nausea and vomiting associated with cancer chemotherapy.

With the change in classification, Marinol can now be prescribed by doctors with the possibility of five prescription refills in six months. The change also eases record-keeping requirements and distribution restrictions on the drug.

Supporters of medical marijuana, however, say patients who use it are able to get the benefits of dozens of other agents in marijuana that are not in Marinol.

Marinol supporters have touted the fact that doctors are able to prescribe a specific dosage of the drug, which they cannot set with marijuana use. The prescribed drug also does not pose the added concern of potential lung damage from smoking marijuana, Marinol advocates have said.