The effectiveness and clinical indications of Terbutaline as a bronchodilator were analyzed by the subcutaneous, oral and aerosol route in 56 patients. A significant improvement in air flow rates both in major and smaller airways was achieved by all routes of administration. The inhalation route offered the fastest onset of action, maximal response and longest duration. Similar trends, but of decreased magnitude, were seen following the subcutaneous and oral routes. Overall analysis of results did not indicate a definite dose-response dependency within the aerosol and oral routes at the tested dosages, whereas the incidence of side effects was clearly dose-dependent. On this basis it is recommended that for maintenance therapy treatment should begin with oral Terbutaline 2.5 mg every 6-8 hours and this dose be adjusted according to the clinical response. For the treatment of acute bronchospasm 0.50 mg or 0.25 mg subcutaneously, or a dose as low as 0.375 mg by aerosol, would be highly effective within five minutes. A combination of oral and aerosol administration represents a highly effective synergistic combination for most clinical situations requiring maintenance therapy.