Appellant’s probation (for a controlled substance offense) was revoked based on possession and use of marijuana. The trial court ruled that Health and Safety Code section 11362.5 (the Compassionate Use Act) did not apply to him because he could not satisfy a medical necessity defense. On appeal, respondent argued that section 11362.5 is not a defense to a revocation of probation, and that possession of marijuana violated a condition of probation to obey the laws. The appellate court disagreed and reversed the order revoking probation. First, the medical necessity defense is not the measure of the right to obtain and use marijuana for medical purposes which is granted by section 11362.5. Second, a defendant may assert section 11362.5 as a defense to a probation revocation where, as here, there is no claim that his conduct endangered others or that the marijuana was used for non-medical purposes. Further, a probation condition which prohibits the lawful use of a prescription drug does not serve a rehabilitative purpose.