But the state warned that registration in the state program won't protect patients or caregivers from federal prosecution for drug possession if the federal government chooses to take action against them.
The Human Services Department stopped sending out the cards - but continued processing applications - after the Supreme Court held last week that federal authorities can prosecute marijuana possession under federal drug laws, even in states like Oregon, where medical use of the drug is legal.
The department was awaiting a review of the Supreme Court's ruling by Oregon Attorney General Hardy Myers. Myers concluded that the ruling did not invalidate the state's program, and the department on Friday began mailing about 550 registration cards that had been held up, said Grant Higginson, a department administrator.
Madeline Martinez, Oregon director of the National Organization to Reform Marijuana Laws, said the court ruling caused many patients to dismantle their gardens.