Abstract: A modified hand-held syringe suitable for medical and biological purposes ving a disposable resilient balloon-like diaphragm for advantageously assuring the delivery of fluid at a more even pressure than that attained by thumb pressure applied to a non-modified syringe. Moreover, the balloon-like structure simultaneously acts as an indicator of excessively applied pressure. Clinically, the device is particularly suited for use with patients having athlerosclorosis, or other diseases affecting cardio-vascular walls. Also, proper use of the device precludes excessive hematoma. In other laboratory and research contexts, the device is particularly suited for the administration of liquid to delicate tissues.