Statistics from the Colorado health department show two doctors are responsible for referring more than a third of the patients on the state's medical-marijuana registry.
The Denver Post reports that of the roughly 10,000 medical-marijuana patients on the registry, 75 percent received their recommendations from one of 15 doctors.
State health department director Jim Martin says it's a cause for concern. Colorado Attorney General John Suthers suggests that the state Board of Medical Examiners investigate the doctors recommending medical marijuana the most often to see if everything is proper.
Cannabis advocates counter that the clustering of referrals is understandable, given that many doctors specialize in a particular area.
The Post says the doctor's names weren't released because of state confidentiality laws.
(Copyright 2009 by The Associated Press. All Rights Reserved.)