Investigations by radioisotope, electromagnetic, and resistographic methods showed that tropaphen increases the cerebral blood flow and lowers the tone of the intracranial vessels. It inhibits reflex responses of intracranial vessels and responses of the intracranial blood flow to stimulation of the cervical sympathetic nerves and it prevents the development of experimental disturbances of the cerebral circulation of neurogenic nature. These effects of tropaphen are due to its α-adrenoblocking properties