Using the atraumatic diagnostic technique of forehead thermography to indirectly evaluate cerebral arterial circulation, nine patients with vascular disease in the extracranial or intracranial carotid arterial system were given 300 mg. papaverine hydrochloride. All patients demonstrated some degree of improvement after the drug was administered as determined by comparing control thermograms to thermograms obtained 1, 4 and 8 hours after administration of the drug. Improvement was attributed to increased cerebral blood flow due to the direct vasodilating effect of papaverine hydrochloride. In conclusion, this study suggests that if potential stroke victims can be detected at an early stage with thermography (and/or with other atraumatic diagnostic techniques), drug therapy may prove to be of immediate therapeutic value. The response of any given patient to drug therapy may be determined simply and atraumatically by thermographic examinations in which each patient is used as his own control.