The research conducted so far in computer assisted learning (CAL) can be categorised in three different levels: the basic level, the component level, and the course or holistic level. Because research in CAL in health education has been driven by enthusiastic teachers, it is well understood that most studies are built around existing structured courses and focus on holistic evaluation of the learning process. There seems to be a lack of original research on the actual role of CAL components in the learning process. The aim of this thesis was to contribute to our understanding of the component level in order to be able to develop better instruments for teaching. This thesis focuses on two different components, video and free text communication (FTC). Four studies were conducted:1. A systematic literature review to investigate the state of the art within CAL in dental and medical education.2. A design and usability test as well as one randomised, controlled trial to investigate the effects of training with FTC on the development of skills in history taking. 3. A randomised, controlled trial to test the learning effect of a segmented vs a whole video.4.A randomised, controlled trial to test the learning effect of segmented video vs live demonstration through a camera.Most of the studies covered in the literature review were conducted at the holistic level and therefore unable to identify the importance of individual CAL functions in the learning process. The students’ ability to take a history of real patients improved significantly after one training session with FTC. The learning outcome of segmented videos appears to be better than that of whole videos, and segmented videos are watched more by the students. The results of the experimental studies indicate that both FTC and video can play significant roles in the CAL process. Research-based development of CAL components would increase the potential of CAL in education.