November 2000 November 2000 development of Colorado laws History of Colorado's Medical Marijuana Laws History of Colorado's Medical Marijuana Laws History of Colorado's Medical Marijuana Laws development of Colorado laws November 2000 November 2000 Amendment 20 development of Colorado laws History of Colorado's Medical Marijuana Laws several legal challenges development of Colorado laws development of Colorado laws Colorado Health Board permitted the new dispensary model development of Colorado laws Colorado’s cannabis history History of Colorado's Medical Marijuana Laws November 2000 History of Colorado's Medical Marijuana Laws medical use was legalized expansion legal since 2000