The California Medical Association, the state’s largest doctor group, on Friday adopted a resolution to support the legalization of marijuana for medical uses, according to the Los Angeles Times.

The group’s support of medical marijuana comes after U.S. prosecutors in California threatened to seize the properties of licensed California marijuana dispensaries if they don’t close up shop within 45 days. U.S. attorneys in California have also threatened to target newspapers, radio stations and other media outlets that advertise for dispensaries.

The California Medical Association said the discrepancy between state and federal law created an untenable situation for physicians. The use of marijuana for medical purposes is legal under California law, but the drug is still classified as a Schedule I substance under federal law, a classification reserved for dangerous drugs with no real medicinal value.

“It’s an uncomfortable position for doctors,” said Dr. Donald Lyman, the physician who wrote the new policy. “It is an open question whether cannabis is useful or not. That question can only be answered once it is legalized and more research is done. Then, and only then, can we know what it is useful for.”

In August, the California Medical Association issued recommendations for physicians on medical marijuana, saying that the drug “may be effective for treatment of nausea, anorexia, pain and other conditions (i.e., spasticity), but that more clinical research is needed regarding specific indications, dosing, and the management of side effects.”