A data base program for some types of patient visits, especially medical procedures, is described. It would be primarily useful as a tool for clinical research, but its implementation would depend on its contributing to the routine documentation of patient visits (i.e. generate typed reports appropriate for charting). To achieve this, and to standardize the information to be collected, several concepts have been developed: a data base template; a branched data structure; bit-mapped, multi-option data fields; and flexible, efficient search capabilities. The program is presently configured for the Apple IIe/IIc and it is not a substitute for keeping patient records (although it may be helpful). It is presented as an approach to the "computerization" of medical information developed through a combined appreciation of basic computer capabilities, and an awareness of how some clinical information may be categorized.