Wound healing is one of the most complex biological processes in an organism. It proceeds in three consecutive stages: the exudative, the proliferative, and the reparative phase. For a better understanding of new treatment possibilities, knowledge of the fundamental principles of these phases is required. Depending on the extent, location, bacterial colonization, and stage of a wound, it is important to find the appropriate treatment modality. In the present article, the basic principles of wound healing and disruptive factors are described in preparation for the next part on modern treatment modalities.