Shawna Brown, co-owner of Denver's Lotus Medical, answers the telephone in waiting area of the dispensary...Denver-based medical marijuana dispensaries --Colorado is one of 19 states to permit the medicinal use of marijuana.  In the city of Denver, well over 100 marijuana dispensaries have sprung up to meet the demand.  Patients are required to register with the state and have a valid doctor's note for dispensaries to sell them marijuana.