Amendment 20 was an amendment to state statutes, submitted for referendum in the 2000 general elections in the U.S. state of Colorado. The amendment was adopted by 54% of participating voters. Under the law, patients may possess up to 2 ounces of medicinal marijuana and may cultivate no more than six marijuana plants (three flowering plants) at a time. Patients who are caught with more than this in their possession may argue "affirmative defense of medical necessity" but are not protected under state law with the rights of those who stay within the guidelines set forth by the state.[4] Background In the years immediately leading up to the Amendment's adoption there was a newfound interest in medical marijuana research. Between 1996 and 2000 eight states approved some form of medical marijuana use. Advocates and opponents both pointed to scientific evidence to make their case. The director of the white house office National Drug Control policy sought clear answers and so they asked a non-governmental body the Institute of Medicine to reviewed the medical data. After eighteen months and considering more than five hundred scientific papers the IOM found that there was remarkable consensus for the potential of cannabinoid based drugs for medical use and almost no data about any proven benefits. Implementation Ten years after the popular adoption of the referendum and the press is already calling it marijuana country. As of April 20, 2010 Denver has two hundred fifty medical marijuana dispensaries in operation and Boulder had one hundred. More than sixty thousand patients held red cards with a six-month waiting list to be added to the growing registry. Experts estimated there may be as many as 100,000 patients in the system. For a patient to access the system they need to get a "doctor's recommendation", which differs from a prescription. This recommendation can be had for about one hundred fifty dollars and may consist of a five to 10-minute conversation. The state recognized recommendation, called a "red card" due to its red color, can be used at any marijuana dispensary in the state; though naming a single marijuana dispensary as a patient's "caregiver' often affords the patient discounts on medicine. Text of referendum Shall there be an amendment to the Colorado Constitution authorizing the medical use of marijuana for persons suffering from debilitating medical conditions, and, in connection therewith, establishing an affirmative defense to Colorado criminal laws for