The health risks for both domestic animals and humans caused by large herbivores in self-sustaining ecosystems are largely unknown. The aim of this article is to make an inventory of these risks, to explore ways to manage them in practice, and to make recommendations for the quantification of risks. Potential hazards from herbivores in and around Europe are listed using the data of the OIE (Office International des Epizooties). The desired health status and the implementation of control or surveillance measures are important factors when assessing the risks. Results indicate that a regular yearly system of health monitoring of herbivores is necessary. To get more insight into the importance of certain risks (Infectious Bovine Rhinotracheitis, biodegradation of carrion in the field) epidemiological investigations have to be carried out to assess the risk of transmission in different situations (with or without intervention). Analysing and managing risks enable decision-makers to formulate the conditions for the development of nature reserves. In Europe more has to be done to increase the quality of nature in terms of de-fragmentation and de-isolation, but regulations concerning the health of large herbivores also have to be improved.