A major problem in outpatient treatment has been the extreme irregularity with which patients use medication prescribed for them. As a new approach to resolving this problem, a portable operant apparatus was developed based on response priming and escape reinforcement. The apparatus sounded a tone at the time that a pill was to be taken. When the user turned a knob to terminate the tone, the apparatus delivered the pill into the user's hand. The apparatus was evaluated with six normal adults using a medically inert pill. A greater proportion of the pills were taken by each subject when using the special apparatus as compared with the use of a portable alarm timer or the usual wristwatch. These results demonstrate a new approach for increasing the regularity of self-administration of medicines.