Disclosed herein is an apparatus and method which are used to improve blood flow in small vessels such as arterioles and capillaries. Method embodiments of the present invention make use of very high frequency (typically 1 MHZ to 100 MHZ) electrical signals in combination with ultrasonic signals typically falling within the same frequency range, where the frequency of the electrical signals and the ultrasonic signals may be the same or different. The electrical signals and ultrasonic signals are applied to a patient simultaneously, typically at a single contact location which is proximate on the exterior of the body to the arterioles and capillaries where blood flow is impaired.