The unanimous decision Tuesday concluded cardholders are immunized because extracts such as cannabis oil and hashish are considered marijuana under the state's 2010 voter-approved medical marijuana law.
The ruling reversed a lower court decision that found patients faced arrest for hashish possession because the drug isn't mentioned or included by name in the law.
The case, which for years has put Arizona's entire medical cannabis industry and 184,000 patients in a kind of limbo, began in March 2013. Rodney Jones, a registered medical marijuana patient, was arrested for possessing 1.4 grams of hashish.
Prosecutors argued that the 2010 Arizona Medical Marijuana Act (AMMA) did not protect Jones, because hashish and other cannabis extracts did not qualify as "marijuana" under the language of the initiative. Marijuana, they contended, only referred to cannabis flower and leaf.