Use of medicinal cannabis is legal if you have a current qualifying physician's recommendation or a valid county-issued medical marijuana identification card. To buy medicinal cannabis, you must be 18 or older and have either have current qualifying physician's recommendation, a valid county-issued medical marijuana identification card or be a Primary Caregiver as defined in Health and Safety Code Section 11362.7(d). With a MMIC, you can possess up to eight ounces of dried cannabis and up to six mature or 12 immature cannabis plants. With a physician's recommendation, you may only possess what the "patient" can consume medically, which is indicated in the recommendation. With a valid county-issued MMIC, you do not have to pay sales tax when you buy cannabis, but you may have to pay other taxes.