States with medical marijuana laws generally have some form of patient registry, which may provide some protection against arrest for possession up to a certain amount of marijuana for personal medicinal use. The primary exception is Maryland, whose statute simply allows for medical purposes as a defense against arrest and prosecution of marijuana possession, but does not provide a means for patients to actually obtain the drug. As of April, 2011, people in Maryland with a debiliating medical condition cannot be prosecuted for non-public use or possession of one ounce or less of marijuana.

Some of the most common policy questions regarding medical marijuana include how to regulate its recommendation, dispensing, and registration of approved patients. Some states and localities without dispensary regulation are experiencing a boom in new businesses, in hopes of being approved before presumably stricter regulations are made. Medical marijuana growers or dispensaries are often called "caregivers" and may be limited to a certain number of plants or products per patient. This issue may also be regulated on a local level, in addition to any state regulation.