The present invention comprises methods and devices for modulating the activity or activities of living cells, such as cells found in or derived from humans, animals, plants, insects, microorganisms and other organisms. Methods of the present invention comprise use of the application of ultrasound, such as low intensity, low frequency ultrasound, to living cells to affect the cells and modulate the cells' activities. Devices of the present invention comprise one or more components for generating ultrasound waves, such as ultrasonic emitters, transducers or piezoelectric transducers, composite transducers, CMUTs, and which may be provided as single or multiple transducers or in an array configurations. The ultrasound waves may be of any shape, and may be focused or unfocused.