Three Swiss university departments of morphology have co-operated to produce a web-based course in human embryology for medical students at the preclinical stage of their education. Web-based training (WBT) lends itself admirably to the teaching of embryology, which forms an important part of a medical students' education. Moreover it permits the display of movement and threedimensionality, both of which are necessary to understand the process of development. The concept of active learning embraces the view that learning is more effective when students become actively engaged in the subject matter and take more responsibility in the learning process. We wished to achieve this goal by incorporating a variety of activities, including links to other specialised web-pages, various levels of complexity, multiple-choice and other types of questions.

The teaching goals of the WBT in embryology are to:

• foster a knowledge of both the mechanisms underlying human gamete development and fusion to form a new organism, and of those directing the subsequent growth, maturation and differentiation of organs and systems.
• cultivate an awareness of the problems possibly occurring at different stages of organ development and of the malformations arising therefrom.
• foster an appreciation of how the environment and drugs can influence embryological development.
• promote competence in the counselling of parents with malformed children.

We thank the Swiss Confederation for having financed half of this project, which was co-financed by our three universities, allowing free access to the course site on a world-wide basis.