U.S. Surgeon General Vivek Murthy expressed optimism about the medical benefits of marijuana use in a Wednesday television interview.

Speaking on CBS This Morning, Murthy said there is some promising research about medical uses of the drug, which is legal in some states but still banned on the federal level. “We have some preliminary data showing that for certain medical conditions and symptoms, that marijuana can be helpful,” Murthy told CBS. “I think that we have to use that data to drive policymaking.”

Murthy added that more research is needed “to see what the science tells us about the efficacy of marijuana,” but he said more data should be on the way thanks to the growing list of states passing laws to legalize medical marijuana.

The Surgeon General’s statements follow what seems to be growing acceptance in the federal government of medical marijuana. In December, Congress passed a spending measure that included a provision to effectively end the federal ban on medical marijuana in states where it is legal.

At the moment, 23 states allow the use of medical marijuana, despite the fact that federal laws still classify marijuana as a Schedule 1 drug — the most dangerous level, which also includes heroin and ecstasy. Four states have passed laws legalizing recreational pot along with Washington, D.C.

At a Senate confirmation hearing last year, some politicians asked Murthy to clarify his stance on marijuana legalization. The physician said at the time that, much like other drugs, he would not recommend that anyone use marijuana. “I don’t think it’s a good habit to use marijuana,” he said.

Still, there is some precedent of U.S. Surgeon Generals showing open minds when it comes to medical marijuana’s potential benefits. Regina Benjamin, who served in the post from 2009 to 2013, acknowledged that the drug could have medicinal uses. But she felt more research was necessary. Former U.S. Surgeon General Joycelyn Elders, who occupied the job in the early 1990’s, said in 2010 that she supported legalization and added that marijuana is not addictive.

UPDATE: Murthy later added clarification in a statement issued by the Department of Health and Human Services on the Surgeon General’s behalf, according to The Huffington Post. In the statement, Murthy said that marijuana policy “should be driven by science.” He goes on to add: “While clinical trials for certain components of marijuana appear promising for some medical conditions, neither the FDA nor the Institute of Medicine have found smoked marijuana to meet the standards for safe and effective medicine for any condition to date.”