Generally, a patient certified for medical marijuana may not possess at any one time more than a 30-day supply of the medicine. However, the law permits patients to obtain a new 30-day supply during the last 7 days of their previous 30-day supply. In the process of certifying the patient, the physician will determine the amount of medicine the patient needs for a 30-day supply. The physician will also prescribe the form and method by which the patient should administer the medicine. Currently, approved forms of medical marijuana are liquids and oil to be used with a vaporizer or an inhaler, and capsules for oral ingestion.