Currently, federal and state laws prohibit the manufacture, delivery, and possession of psilocybin (psychoactive mushroom). Initiative amends state law to require Oregon Health Authority (OHA) to establish Oregon Psilocybin Services Program to allow licensed/regulated production, processing, delivery, possession of psilocybin exclusively for the administration of 'psilocybin services' (defined) by licensed 'facilitator' (defined) to 'qualified client' (defined). Grants OHA authority to implement, administer, and enforce the program. Imposes two year development period before implementation of the program. Establishes fund for program administration and governor-appointed advisory board that must initially include one measure sponsor; members are compensated. Imposes packaging, labeling, and dosage requirements. Requires sales tax for retail psilocybin. Preempts local laws inconsistent with program except 'reasonable regulations' (defined). Exempts licensed/regulated activities from criminal penalties. Other provisions.