To develop an interactive multimedia-based computer-aided instruction (CAI) programme, to determine its educational worth and efficacy in a multicultural academic environment and to evaluate its usage by students with differing levels of computer literacy. A prospective descriptive study evaluating pre- and post-module testing, student usage tracking and a questionnaire survey. University of Natal Medical School. Thirty-four volunteers from the class of 125 second-year M.B. Ch.B. students who participated in the CAI study; 13 of these were not computer-literate. The study group used the CAI module for 2 weeks as part of the course. Post-test scoring and evaluation of questionnaire responses. Results of pre- and post-tests show that CAI users' scores were slightly lower on pre-testing (22.1% v. 23.2%), while their post-test scores were higher (65.6% v. 60.7%). Lack of computer literacy did not restrict or hinder students in their use of the programme. Responses to a questionnaire completed by all CAI users indicate consensus that the programme helped the students to learn (94%), that it provided important basic knowledge (88%) and that it was a helpful learning experience (88%). All but 1 student wished to have more programmes like this available in histology. The CAI programme reduced the time spent by students in the histology microscopy laboratory and did not negatively affect their marks in post-course evaluation. The concept of multimedia-based CAI in medical education was positively received by the students who participated.