There are approximately 2.7 million adult medical marijuana users according to recent data from the US National Survey on Drug Use and Health (NSDUH). This estimate is based on a household survey of almost 68,000 people 12 year and older, covering all 50 states and the District of Columbia.
Approximately 29.8 million adults use marijuana each year. Those who had used marijuana in the past year were asked, “Was any of your marijuana use in the past 12 months recommended by a doctor or other health care professional?” About 9.1% (2.7 million) said they had used some medical marijuana in the last year, while 5.1% (1.7 million) had only used medical marijuana.
The estimated number of medical marijuana users in the US is higher than a previously reported estimate of 1.1 million based on the number of registered medical marijuana patients (http://medicalmarijuana.procon.org/view.resource.php?resourceID=005889).