Wiki tools, which became known mainly thanks to the Wikipedia encyclopedia, represent quite a new phenomenon on the Internet. The work presented here deals with three areas connected to a possible use of wiki tools for the preparation of an e-learning course. To what extent does Wikipedia.com contain terms necessary for scientific lectures at the university level and to what extent are they localised into other languages? The second area covers the use of Wikipedia as a knowledge base for e-learning study materials. Our experience with Enviwiki which originated within the E-V Learn project and its use in e-learning courses is presented. The third area aims at the use of wiki tools for building a knowledge base and sharing experience of the participants of an e-learning course. (Contains 5 figures.)