If you have a chronic illness or medical issue that allows you to use marijuana legally under California’s medical marijuana law, you may be eligible for a Medical Marijuana Identification Card. The statewide program is administered locally by the Public Health Department. Eligible patients and their primary caregivers can apply for the card, which may protect against wrongful arrest and prosecution for the possession and use of marijuana for medical purposes, although it does not prevent federal prosecution. You must provide written documentation from a licensed physician verifying that medical marijuana is needed to treat your medical condition, proof of residency, and photo identification.