Doctors today might face the question of whether it's a good idea to recommend marijuana smoking to patients, but that's only "a short-term consideration," said the directors of a groundbreaking study on the value of marijuana as medicine that was released Wednesday.

In the long run, researchers need to find ways to deliver the quick hit that smoked marijuana delivers without the tar and the lung-irritating smoke that comes with smoking it, they said.

During the study, done by the Institute of Medicine for the White House Office of National Drug Control Policy, "we uncovered an explosion of new scientific knowledge about how active components in marijuana affect the body and how they might be used in a medical context," said study co-director John Benson of Portland, Ore.