Oregon Revised Statutes Alcoholic Liquors; Controlled Substances; Drugs § 475B.480

(1) Except as provided in ORS 475B.478, a person has an affirmative defense to a criminal charge of possession, delivery or manufacture of marijuana, or any other criminal offense in which possession, delivery or manufacture of marijuana is an element, if the person charged with the offense:

(2) A person does not need to lawfully possess a registry identification card to assert the affirmative defense established in this section.

(3) A person engaged in the medical use of marijuana who claims that marijuana provides medically necessary benefits and who is charged with a crime pertaining to the use of marijuana is not precluded from presenting a defense of choice of evils, as set forth in ORS 161.200, or from presenting evidence supporting the necessity of marijuana for treatment of a specific disease or medical condition, provided that:

(4) A defendant proposing to use the affirmative defense established in this section in a criminal action shall, not less than five days before the trial of the cause, file and serve upon the district attorney a written notice of the intention to assert the affirmative defense. The notice must specifically state the reasons why the defendant is entitled to assert the affirmative defense and the factual basis for the affirmative defense. If the defendant fails to file and serve the notice, the defendant is not permitted to assert the affirmative defense at the trial of the cause unless the court orders, for good cause, otherwise.