For decades, Oregon has been a trailblazer in progressive cannabis culture. In 1973 it became the first state to decriminalize possession and use. In 1998, The Oregon Medical Marijuana Act allowed cannabis to be cultivated, purchased and used by medical patients for certain ailments, including severe pain, nausea, cancer, HIV/AIDS, and epilepsy. 

http://theglobalgrid.org/legalized-cannabis-land-use-regulations-portland-oregon/