California became the first state to enact protections for medical cannabis patients and their primary caregivers when voters approved Proposition 215, the Compassionate Use Act, in 1996. The state’s legislature subsequently passed the Medical Marijuana Program Act in February 2003, establishing a voluntary ID card program and a legal framework for collectives and coops to distribute medical cannabis as well as protections for transporting cannabis. Both measures have been subject to differing legal interpretations, particular in regard to the sale of cannabis through storefront dispensaries, that have been litigated before the California Supreme Court.
Patients and their caregivers are permitted to legally use, possess, and grow cannabis for medical purposes. The law also protects not-for-profit collective and cooperatives and allows primary caregivers to be reimbursed for the costs of their services.
To be a legal medical cannabis patient in California, you need a recommendation from a licensed physician. California’s medical cannabis law allows doctors to recommend cannabis for any serious or persistent medical condition that may be treatable with cannabis, including AIDS, anorexia, arthritis, cachexia, cancer, chronic pain, glaucoma, migraine, persistent muscle spasms, seizures, and severe nausea.
The legislature has established a voluntary California medical cannabis registry that issues ID cards through each county’s health department. A state-issued ID card is not required to be a legal patient, but it offers protection from arrest for patients in possession of no more than eight ounces of useable cannabis or cultivating no more than six mature or twelve immature plants. Patients and their designated caregivers without a state ID card or those in possession of larger quantities are afforded an affirmative defense, if charged. Patients may cultivate or possess any quantity reasonably necessary for managing their medical condition. Qualified patients on probation or parole may legally use medical cannabis with the consent of their probation or parole officer.
Patients may form not-for-profit collectives and coops to cultivate and distribute medical cannabis. These coops and collectives may operate dispensaries that provide cannabis for sale to qualified patients, but municipalities may restrict or ban the operation of dispensaries in their jurisdiction.
Laws: 
Proposition 215, the “Compassionate Use Act”
The Compassionate Use Act is a voter initative, passed in 1996, that made California the first state to legalize cannabisfor medical use
California Senate Bill 420, the Medical Marijuana Program Act
This bill was passed in 2004 with the following purpose: “(1) Clarify the scope of the application of the act and facilitate the prompt identification of qualified patients and their designated primary caregivers in order to avoid unnecessary arrest and prosecution of these individuals and provide needed guidance to law enforcement officers. (2) Promote uniform and consistent application of the act among the counties within the state. (3) Enhance the access of patients and caregivers to medical marijuana through collective, cooperative cultivation projects.”
California Assembly Bill 1300
This bill amends the Medical marijuana Program Act to specify that nothing in that Section prevents a city or county from “[a]dopting local ordinances that regulate the location, operation, or establishment of a medical marijuana cooperative or collective.”
California Assembly Bill 2650
This bill prevents any medical cannabis cooperative, collective, dispensary, operator, establishment, or provider authorized by law to possess, cultivate, or distribute medical cannabis that has a storefront or mobile retail outlet which ordinarily requires a local business license shall be located within a 600-foot radius of any public or private school providing instruction in kindergarten or grades 1 to 12.
California County and City Medical Cannabis Laws
Municipalities and counties in CA have chosen in some cases to create their own guidelines to further clarify the 1996 Compassionate Use Act and SB 420. This listing gives up-to-date guidelines for counties that have implemented them.
Regulations:
SB 420, the Medical Marijuana Program Act, left dispensary regulations up to cities and counties. Patient and Caregiver IDs are not mandatory but can be acquired through county Departments of Public Health.