Abstract: Portable electronic medical apparatus for controlling the flow rate of a fluid for medically treating a patient may receive flow rate information representing sequences of up to 20 flow rates and their durations from an individual and from an electronic data processor, and operate continuously without the presence of an operator for in the range of 40 hours. Upon the incorporation of an infusion pump into the apparatus, the desired regimen of treatment may be accomplished; and through a keyboard input for the apparatus, an operator may in certain respects modify a regimen which is being carried out. Safety features in the apparatus include: a frequency detector for monitoring the frequency of a clocking signal for the apparatus; the selective testing of output signals of the apparatus, the portable power supply for the apparatus and the frequency detector against stored predetermined standards; and the provision of warning signals to an operator to indicate divergences from such standards.